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MathLover1 answered: 6636 problems
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logarithm/694868: evaluate the logarithm
+log%283%2Csqrt%283%29%29+
1 solutions

Answer 428232 by MathLover1(6638) About Me  on 2012-12-16 16:04:45 (Show Source):
You can put this solution on YOUR website!

log+%283+%2Csqrt+%283%29%29...in base 10 you will have

=log+%28sqrt+%283%29%29%2Flog+%283%29+.........log+%28sqrt+%283%29%29=log+%283%5E%281%2F2%29%29=%28log%283%29%29%2F%282+log%2810%29%29

=%28log%283%29%29%2F%282+log%2810%29%29%2Flog+%283%29+

=%28cross%28log%283%29%29%29%2F%282+log%2810%29%29%2Fcross%28log+%283%29%29+

=1%2F%282+log%2810%29%29+.......2+log%2810%29=log%2810%5E2%29=2

=1%2F2+


Functions/694712: Is this a function: {(x.y) | x^2 +(y-1)^2 = 4}
1 solutions

Answer 428183 by MathLover1(6638) About Me  on 2012-12-16 11:50:11 (Show Source):
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{(x.y) | x%5E2+%2B%28y-1%29%5E2+=+4}
What is a Function?
A function relates an+input to an+output.
A function is a rule that assigns uniquely to a member of domain+set, a member of the range set. The key word is "uniquely".
So if you assign say x=2 as well as x=-2 to number y=1, then you have a rule, but not a function. That is the logic behind the vertical+line+test. If you draw a vertical line and it intersects the graph of the function in two+distinct+points, then you can see that it means you have assigned both of these points to the point where your vertical line crosses the x-axis.
An example of this is the circle, and you have a circle.




decimal-numbers/694764: Hi, I am currently struggling with algebra 1. I'm in grade eight. I need to figure out how to write an inverse variation if y varies inversely with x. please tell me how to solve x=3 when y=2
1 solutions

Answer 428175 by MathLover1(6638) About Me  on 2012-12-16 11:10:06 (Show Source):
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if y varies inversely with x, than you have a constant of proportionality k which makes y=k%2Fx

then you need to find k, the constant of proportionality

y=k%2Fx... now plug in given values x=3 and y=2
2=k%2F3
k+=+2%2A3
k+=+6


Functions/694630: rewrite function f(x)=-1/3x2-2x-9 in the form f(x)=a(x-h)2+k
give x and y intercepts
give domain and range
1 solutions

Answer 428100 by MathLover1(6638) About Me  on 2012-12-15 20:15:57 (Show Source):
You can put this solution on YOUR website!
f%28x%29=-%281%2F3%29x%5E2-2x-9 in the form f%28x%29=a%28x-h%29%5E2%2Bk
Solved by pluggable solver: Completing the Square to Get a Quadratic into Vertex Form


y=-0.333333333333333+x%5E2-2+x-9 Start with the given equation

Error: 'Illegal modulus zero at (eval 1373) line 20. '. Illegal modulus zero at (eval 1373) line 20.
error_location: 13


+x-intercept ......set f%28x%29=0
0=-%281%2F3%29x%5E2-2x-9...use quadratic formula to solve for x

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+



x+=+%282+%2B-+sqrt%284-12+%29%29%2F%28-2%2F3%29%29+

x+=+%282+%2B-+sqrt%28-8+%29%29%2F%28-2%2F3%29%29+

x+=+%282+%2B-+2.83%2Ai%29%2F%28-2%2F3%29%29+

x+=+3%282+%2B-+2.83%2Ai%29%2F-2+

x+=+%286+%2B-+8.49%2Ai%29%2F-2+
x+=+%286%2F-2+%2B-+8.49%2Ai%2F-2%29+

x+=+-3+%2B-+4.245%2Ai+....so, we have two complex solutions, it means there is no real solutions and there is no +x-intercepts

and y-intercept......set x=0
f%28x%29=-%281%2F3%290%5E2-2%2A0-9
f%28x%29=0-0-9
f%28x%29=-9.......y-intercept is at (0,-9)

see it on a graph:
+graph%28+600%2C+600%2C+-10%2C10%2C+-15%2C+10%2C+-%281%2F3%29x%5E2-2x-9%29+

domain:



range:





Graphs/694626: Can anyone help me graph this inequality?
y is less than or equal to 2x + 1

1 solutions

Answer 428082 by MathLover1(6638) About Me  on 2012-12-15 18:55:32 (Show Source):
You can put this solution on YOUR website!
y+%3C=2x+%2B+1.....first graph it as equation y+=2x+%2B+1
find x-intercept and x-intercept

to find x-intercept, set y=0

0=2x+%2B+1
-1=2x
highlight%28-1%2F2=x%29

to find y-intercept, set x=0

y=2%2A0%2B+1
y=0%2B1
highlight%28y=1%29

plot these points and draw a line


now shade everything to the right from a line




Graphs/694619: I am having trouble solving the relationship between x and f(x) for the following
input output
-1 3
0 2
1 1
1 solutions

Answer 428079 by MathLover1(6638) About Me  on 2012-12-15 18:46:42 (Show Source):
You can put this solution on YOUR website!
the relationship between x and f%28x%29 for the following
f%28x%29=ax%2Bb or y=ax%2Bb
given:
input output
x...........f%28x%29 or y
-1 +3
0 2
1 1
so, you are given three points which you can plot on a Cartesian coordinate system and graph a line that contains these points
(x,y)= (-1,3)
(x,y)= (0,2)...this is y-intercept
(x,y)= (1,1)
now we can find the equation of a line passing through these points
Solved by pluggable solver: FIND EQUATION of straight line given 2 points
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (1, 1) and (x2, y2) = (0, 2).
Slope a is a+=+%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29+=+%282-1%29%2F%280-1%29+=+-1.
Intercept is found from equation a%2Ax%5B1%5D%2Bb+=+y%5B1%5D, or -1%2A1+%2Bb+=+2. From that,
intercept b is b=y%5B1%5D-a%2Ax%5B1%5D, or b=1--1%2A1+=+2.

y=(-1)x + (2)

Your graph:




so,the equation of a line passing through these points is y=-x%2B2 where a=-1 and b=2
now we can check if all three given points lie on this line


as you can see, all three given points do lie on this line



Probability-and-statistics/694369: Find each probability
a. P(5;4)
b. P(2;4)
c. P(6;3)
d. P(10;7)
e. P(9;8)

Part 2
A copy machine randomly puts out 10 blank sheets per 500 copies processed. Find the probability that in a run of 300 copies, 5 sheets of paper will be blank.
Part 3
A recent study of robberies for a certain geographic region showed an average of 1 robbery per 20,000 people. In a city of 80,000 people, find the probability of the following:
a. 0 robberies
b. 1 robbery
c. 2 robberies
d. 3 or more robberies

part 4.
In a 400 page manuscript, there are 200 randomly distributed misprints. If a page is selected, find the probability that it has 1 misprint.
1 solutions

Answer 427900 by MathLover1(6638) About Me  on 2012-12-14 18:17:25 (Show Source):
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1.
Probability of event A that occurs:
P%28A%29+=+n%28A%29+%2F+n%28S%29
P%28A%29+=+4+%2F+5
P%28A%29+=+highlight%280.8%29
Probability of event A that does not occur:
P(A') = 1+-+P%28A%29
P(A') = 1+-++0.8
P(A')= 0.2

2.
A copy machine randomly puts out 10 blank sheets per 500 copies processed.
p=10%2F500=highlight%280.02%29
the probability that in a run of 300+copies, 5+sheets of paper will be blank is
p=5%2F300=0.016666666666666666666666666666667highlight%28p=0.017%29
3.
Prob%28+a+robbery%29+=+20000%2F80000=1%2F4+=+0.25
n=80000
The Binomial distribution has the probability
function P%28x=r%29=+nCr+p%5Er+%281-p%29%5E%28n-r%29
r=0,1,2,.....,n
where nCr+=+n%21+%2F+%28r%21+%28n-r%29%21%29
For 80000 people, we expect 4 robberies.
a)
n=80000
p=4%2F80000
p=1%2F20000
highlight%28r=0.00005%29


use the source to compute
%2880000C0%29%281%2F20000%29%5E0%2819999%2F20000%29%5E8000=+0.018
Using Poisson with lambda+=4
P%28x=0%29=+e%5E-4+%2A%284%5E0+%2F+1%21%29=0.018%281%2F1%29=highlight%280.018%29

b)

highlight%28r=1%29
Using Poisson with lambda=4
e%5E-4%284%5E1+%2F+1%21%29=0.018%2A4=highlight%280.072%29

c)
highlight%28r=3%29


d)
p( highlight(x >=3))= p( 3 through 20000)
np=80000%280.00005%29=4
variance=np%281-p%29=3.99998
sd=1.99999
P%28+x+%3E=3%29+=+P%28+z+%3E%283-4%29%2F2%29+=+p%28+z+%3E+-0.5%29=highlight%280.6915%29
This uses normal approximation instead of Binomial because n is too large and p is too small.
4.
Presuming there are 200 of 400 total pages with misprints, there is a 50% probability of discovering one on any given page.
p=200%2F400=1%2F2=0.50 which is highlight%2850%29%



Quadratic_Equations/694354: Please help me solve this equation: 3x^2 - 9x + 1 = 0
1 solutions

Answer 427843 by MathLover1(6638) About Me  on 2012-12-14 13:42:07 (Show Source):
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3x%5E2+-+9x+%2B+1+=+0...use quadratic formula

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ..you have a=3,b=-9, and c=1

x+=+%28-%28-9%29+%2B-+sqrt%28+%28-9%29%5E2-4%2A3%2A1+%29%29%2F%282%2A3%29+

x+=+%289+%2B-+sqrt%2881-12%29%29%2F6+

x+=+%289+%2B-+sqrt%2869%29%29%2F6+

x+=+%289+%2B-+8.3066238629180748525842627449075%29%2F6+

x+=+%289+%2B-+8.31%29%2F6+

solutions:

x+=+%289+%2B+8.31%29%2F6+
x+=+17.31%2F6+
x+=+2.885+
or
x+=+%289+-+8.31%29%2F6+
x+=+0.69%2F6+
x+=+0.115+



Expressions-with-variables/694336: 48>=6-7a
1 solutions

Answer 427836 by MathLover1(6638) About Me  on 2012-12-14 11:53:53 (Show Source):


Numeric_Fractions/694337: 18a^2 + 4 - [6 (a^2 - 2) + 5] =
1 solutions

Answer 427835 by MathLover1(6638) About Me  on 2012-12-14 11:48:12 (Show Source):
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18a%5E2+%2B+4+-+%286+%28a%5E2+-+2%29+%2B+5%29...first multiply 6+%28a%5E2+-+2%29+

=18a%5E2+%2B+4+-+%286a%5E2+-+12+%2B+5%29..add -+12+%2B+5%29

=18a%5E2+%2B+4+-%286a%5E2+-7%29..eliminate parentheses -%286a%5E2+-7%29, be careful with a minus sign in front of parentheses

=18a%5E2+%2B+4+-6a%5E2+%2B7

=18a%5E2+-6a%5E2+%2B+4+%2B7

=12a%5E2+%2B+11




Probability-and-statistics/694295: The sum of the probabilities of complementary events is equal to 1.
Choose one answer.

a. True

b. False
Question 3
Marks: 3
Thirty people were asked about their favorite color, 10 said red, 15 said green, and 5 said blue. What is the probability that a person chosen has a favorite color of red or blue?
Choose one answer.

a. 50%

b. 83%

c. 33%

d. 67%

1 solutions

Answer 427829 by MathLover1(6638) About Me  on 2012-12-14 11:11:31 (Show Source):
You can put this solution on YOUR website!
1.
answer:
a. true
The sum of the probabilities of complementary events is 1.
P(A) + P(A') = 1

2.

answer is: a. 50%
if 10 red,the probability a person chosen has a favorite color of red is 10%2F30=1%2F3=0.33333333333333333333333333333333
and if 5 blue, the probability a person chosen has a favorite color of blue is 5%2F30=1%2F6=0.16666666666666666666666666666667
so, the probability a person chosen has a favorite color of red and blue is 0.50 or 50%






Surface-area/694290: slant height of frustum of cone is 5cm .if difference between radius of its two circular ends is 4cm .write the height of frustum.

1 solutions

Answer 427820 by MathLover1(6638) About Me  on 2012-12-14 09:27:22 (Show Source):
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make a sketch of its cross section and draw in the height
I see a right -angled triangle with height h, so that
l%5E2=h%5E2%2B%28R-r%29%5E2...where R and r are radii of the base, h is height, and l is slant_height

given:
l=5cm
the difference between radius of its two circular ends is %28R-r%29=+4cm
l%5E2=h%5E2%2B%28R-r%29%5E2....plug in given values
5%5E2=h%5E2%2B4%5E2
25+=h%5E2+%2B+16
h%5E2+=+25-16
h%5E2+=+9
highlight%28h+=+3cm%29
as you can see, the infamous 3-4-5 right-angled triangle



Triangles/694162: In a triangle, angle A is 60 percent of angle C, and angle B is 150 percent of angle A.
How many degrees does the smallest angle of the triangle measure?
1 solutions

Answer 427766 by MathLover1(6638) About Me  on 2012-12-13 21:06:08 (Show Source):
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In a triangle the sum of angles is A%2BB%2BC=180 degrees.

if angle A is 60 percent of angle C,than
A=%2860%2F100%29C.....=>...A=0.60C

and if angle B is 150 percent of angle A, than
B=%28150%2F100%29A....=>...B=1.5%280.60C%29=>...B=0.9C%29
so, plug it in A%2BB%2BC=180
0.60C%2B0.9C%2BC=180.....solve for C
2.5C=180
C=180%2F2.5
highlight%28C=72%29
=>...A=0.60C
A=0.60%2A72
highlight%28A=43.2%29
=>...B=0.9C%29
B=0.9C%29
B=0.9%2A72%29
highlight%28B=64.8%29%29
so, the smallest angle of the triangle measure highlight%2843.2%29


Numeric_Fractions/694156: What is negative 4 times two-thirds?
1 solutions

Answer 427762 by MathLover1(6638) About Me  on 2012-12-13 20:53:35 (Show Source):


logarithm/694145: 2lnx=3ln4
1 solutions

Answer 427755 by MathLover1(6638) About Me  on 2012-12-13 20:46:51 (Show Source):
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2ln%28x%29=3ln%284%29

ln%28x%5E2%29=ln%284%5E3%29
ln%28x%5E2%29=ln%2864%29
x%5E2=64
x=sqrt%2864%29...we take only positive root
so, x=8





Graphs/693896: What is the slope of the line passing through the points (2, 5) and (0, -4?
1 solutions

Answer 427617 by MathLover1(6638) About Me  on 2012-12-13 12:09:32 (Show Source):
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Solved by pluggable solver: FIND EQUATION of straight line given 2 points
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (2, 5) and (x2, y2) = (0, -4).
Slope a is a+=+%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29+=+%28-4-5%29%2F%280-2%29+=+4.5.
Intercept is found from equation a%2Ax%5B1%5D%2Bb+=+y%5B1%5D, or 4.5%2A2+%2Bb+=+-4. From that,
intercept b is b=y%5B1%5D-a%2Ax%5B1%5D, or b=5-4.5%2A2+=+-4.

y=(4.5)x + (-4)

Your graph:




Money_Word_Problems/693846: How much simple interest would be paid on a loan of $2720 at 14% for 3 years?
1 solutions

Answer 427580 by MathLover1(6638) About Me  on 2012-12-13 09:18:00 (Show Source):
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Simple interest is calculated on the original principal only.
Simple_+Interest+=+p+%2A+i+%2A+n
where:
p = principal (original amount borrowed or loaned)
i = interest rate for one period
n = number of periods
so, if you have a loan of $p=2720 at i=14% annually for n=3 years, you will pay:
$Simple_+Interest+=+p+%2A+i+%2A+n
$Simple_+Interest=2720%2814%2F100%29%2A3
$Simple_+Interest=2720%2A0.14%2A3
$Simple_+Interest=380.8%2A3
$Simple_+Interest=1142.4


Angles/693845: How to calculate complementary angle of 20 degree 5 minute.
If i subtract 90 degree - 20 degree 5 minute
i get 89 degree 60 minute - 20 degree 50 minute
= 69 degree 10 minute.
But ans should be 69 degree 5 minute. How to get this. Please help.
1 solutions

Answer 427578 by MathLover1(6638) About Me  on 2012-12-13 09:05:55 (Show Source):
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90° - 20°+5'
89°+60' - 20°+5'
(89° - 20°)+(+60'-+5')
(69°+55'.....answer

so, ans could not be 69 degree 5 minutes because you subtracting +5' from +60'


Geometry_Word_Problems/693724: a cubic iron grid has side length 10m. find the length of the diagonal brace of the cube
1 solutions

Answer 427525 by MathLover1(6638) About Me  on 2012-12-12 22:15:48 (Show Source):
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given:
side length a=10m

use Pythagorean theorem to find first the length of shorter diagonal AE=d%5B1%5D:
d%5B1%5D%5E2=a%5E2%2Ba%5E2
d%5B1%5D%5E2=10%5E2%2B10%5E2
d%5B1%5D%5E2=100%2B100
d%5B1%5D%5E2=200
d%5B1%5D=sqrt%28200%29
highlight%28d%5B1%5D=14.14%29
now we can find longer diagonal (AF=d) as a hypotenuse of a right-angle triangle AEF
d%5E2=d%5B1%5D%5E2%2Ba%5E2
d%5E2=%2814.14%29%5E2%2B10%5E2
d%5E2=200%2B100
d%5E2=300
d=sqrt%28300%29
highlight%28d=17.32%29


Linear-equations/693431: Graph a line going through (4,-1) that is parallel to 3x - y = 5x + 2y
Thank you
1 solutions

Answer 427393 by MathLover1(6638) About Me  on 2012-12-12 14:07:50 (Show Source):
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a line going through (4,-1) that is parallel to 3x+-+y+=+5x+%2B+2y

first solve for y

3x+-+y+=+5x+%2B+2y.......move -y to the right and 5x to the left

3x+-+5x+=+2y-y

+-2x+=y

Solved by pluggable solver: Finding the Equation of a Line Parallel or Perpendicular to a Given Line


Since any two parallel lines have the same slope we know the slope of the unknown line is -2 (its from the slope of y=-2%2Ax%2B0 which is also -2). Also since the unknown line goes through (4,-1), we can find the equation by plugging in this info into the point-slope formula

Point-Slope Formula:

y-y%5B1%5D=m%28x-x%5B1%5D%29 where m is the slope and (x%5B1%5D,y%5B1%5D) is the given point



y%2B1=-2%2A%28x-4%29 Plug in m=-2, x%5B1%5D=4, and y%5B1%5D=-1



y%2B1=-2%2Ax%2B%282%29%284%29 Distribute -2



y%2B1=-2%2Ax%2B8 Multiply



y=-2%2Ax%2B8-1Subtract -1 from both sides to isolate y

y=-2%2Ax%2B7 Combine like terms

So the equation of the line that is parallel to y=-2%2Ax%2B0 and goes through (4,-1) is y=-2%2Ax%2B7


So here are the graphs of the equations y=-2%2Ax%2B0 and y=-2%2Ax%2B7



graph of the given equation y=-2%2Ax%2B0 (red) and graph of the line y=-2%2Ax%2B7(green) that is parallel to the given graph and goes through (4,-1)






Functions/693436: how do i do Given the function, (1/3X) + 3/4 = Y, what is Y when X = 1?
1 solutions

Answer 427392 by MathLover1(6638) About Me  on 2012-12-12 13:59:35 (Show Source):
You can put this solution on YOUR website!
if you have this:
%281%2F3%29x+%2B+3%2F4+=+y, what is y when x+=+1
plug in x+=+1
%281%2F3%29%2A1+%2B+3%2F4+=+y

1%2F3+%2B+3%2F4+=+y

4%2A1%2F%283%2A4%29+%2B+3%2A3%2F%284%2A3%29+=+y

4%2F12+%2B+9%2F12+=+y

13%2F12+=+y

1.0833333333333333333333333333333=+y
y=1.08

+graph%28+600%2C600%2C+-5%2C+5%2C+-5%2C+5%2C+%281%2F3%29x+%2B+3%2F4%29+

but, if you have this:
%281%2F3x%29+%2B+3%2F4+=+y, what is y when x+=+1
plug in x+=+1
%281%2F3%2A1%29+%2B+3%2F4+=+y

1%2F3+%2B+3%2F4+=+y

4%2A1%2F%283%2A4%29+%2B+3%2A3%2F%284%2A3%29+=+y

4%2F12+%2B+9%2F12+=+y

13%2F12+=+y

1.0833333333333333333333333333333=+y

y=1.08

+graph%28+600%2C600%2C+-5%2C+5%2C+-5%2C5%2C+1%2F%283x%29+%2B3%2F4%29+
as you can see, in both cases the solution happens to be same


test/693332: 1 + 1 =
1 solutions

Answer 427364 by MathLover1(6638) About Me  on 2012-12-12 09:48:01 (Show Source):
You can put this solution on YOUR website!
test is OK...post your question


Trigonometry-basics/693319: (x+(x^-2))/(1+(x^-2))
1 solutions

Answer 427360 by MathLover1(6638) About Me  on 2012-12-12 09:37:08 (Show Source):
You can put this solution on YOUR website!
%28x%2B%28x%5E%28-2%29%29%29%2F%281%2B%28x%5E%28-2%29%29%29

%28x%2B%281%2Fx%5E2%29%29%2F%281%2B%281%2Fx%5E2%29%29

%28%28x%2Ax%5E2%2B1%29%2Fx%5E2%29%2F%28%281%2Ax%5E2%2B1%29%2Fx%5E2%29

%28%28x%5E3%2B1%29%2Fx%5E2%29%2F%28%28x%5E2%2B1%29%2Fx%5E2%29

%28%28x%5E3%2B1%29%2Fcross%28x%5E2%29%29%2F%28%28x%5E2%2B1%29%2Fcross%28x%5E2%29%29

%28x%5E3%2B1%29%2F%28x%5E2%2B1%29
roots:
real root x%5E2%2B1=0.....=>.......x%5E2=-1 =>.......x=-1
complex root %28x%5E3%2B1%29=0....=>....x%5E3=-1...=>....x=root%283%2C-1%29


because you have 1%2Fx%5E2, and because denominator cannot be equal to zero. you have

a domain:



and the range is:





Expressions-with-variables/693317: I have a question about elimination i have alot of trouble doing it and i need help understanding whats its used for and how its different from substitutions. it would be really great if you could help thank. sincerly,user
1 solutions

Answer 427355 by MathLover1(6638) About Me  on 2012-12-12 09:19:01 (Show Source):
You can put this solution on YOUR website!
here is very good explanation for your question:

about elimination


W3C click on this link



about substitution


W3C click on this link



Graphs/692901: Sketch a graph and shade in the portion that would represent the solution
x + y > 2


1 solutions

Answer 427133 by MathLover1(6638) About Me  on 2012-12-11 14:03:51 (Show Source):


Circles/692844: A pleasant day Sir/ Madam, my daughter has this problem in geometry and I am not good in geometric proofs, can you please help me?
the illustration or drawing is a rectangle inscribed in a circle
Given: Quadrilateral ABCD is a rectangle
Prove: line segment AC and line segment BD are diameters of the circle
Thank you very much for anyone who can help me!
1 solutions

Answer 427124 by MathLover1(6638) About Me  on 2012-12-11 13:12:06 (Show Source):
You can put this solution on YOUR website!

first draw the picture:


next, we will need to prove this:
theorem: Diagonal of any rectangle inscribed in a circle is a diameter of the circle. (
This is essentially the converse of Thales' theorem.
Let A, B, C and D be the vertices of a rectangle inscribed in a circle and let AC and BD be the diagonals of this rectangle.
We can now focus on any one of the four triangles:
ABC, BCD, CDA and DAB
Let's take ABC:
AC side of this triangle is the diagonal of the rectangle
AB and BC are two sides of the rectangle, which potentially may be of different length (but we will prove they must be the same if the area of the inscribed rectangle is maximized).
The angle at B is the right angle since it is one of the angles of the rectangle, which by definition has four right angles.
Hence, looking at the triangle+ABC, we can see that this is a right-angled triangle inscribed in the circle.
Therefore to prove (1), we need to show that side+AC of any such triangle must be a diameter of circle.
Proof:
Choose any three points A, B and C on the circle and connect these points to make a triangle ABC.
Let's suppose that the claim is that the angle at B is right angle.
We will show that if this is true then it must follow that AC is a diameter of the circle.
Connect the center of the circle (O) with each of the vertices of the triangle creating the segments OA, OB and OC.
Let's call the angle defined by the path OAB as alpha and the angle defined by the path OCB as beta.
Since OA, OC+and+OB are all of equal length (equal to the length of the radius of the circle ) then all+three+inner+triangles (OAB, OAC and OBC) are isosceles.
We will next want to find the angle between OA and OC+(the angle at O made out by segments OA and OC) using only angles alpha and betaas given.
The angle between OA and OB is equal to 180+-+2alpha° (due to the fact that OAB is isosceles and the fact that the sum of all three internal angles in a triangle sum to 180°).
Similarly, the angle between OB and OC is equal to 180+-+2beta°.
Finally, since all the three angles at O add up to 360° (full circle), it follows that the angle between OA and OC is equal to 360+-+%28180+-+alpha%29+%96+%28180+-+beta%29+=+2%28alpha%2Bbeta%29.
However, the angle at B of the original triangle ABC is equal to %28alpha%2Bbeta%29 (follows from the fact that OAB and OBC triangles are isosceles).
This angle was claimed to be 90° and therefore the angle between OA and OC is equal to 180°.
This means that the points A and C and the center of the circle (O) are collinear.
In other words, the center of the circle is lying on the straight line segment AC, which in turn means that AC+must be a diameter+of the+circle.
So, we can conclude that each+diagonal of the rectangle inscribed in a circle must be a circles diameter.


Linear-equations/692821: -6 ≤ 2 - 3m ≤ 7

1 solutions

Answer 427104 by MathLover1(6638) About Me  on 2012-12-11 10:35:37 (Show Source):
You can put this solution on YOUR website!

-6+%3C=+2+-+3m+%3C=+7
-6-2+%3C=+2-2+-+3m+%3C=+7-2
-8+%3C=+-+3m+%3C=+5
-8%2F3+%3C=+-+3m%2F3+%3C=+5%2F3
-8%2F3+%3C=+-m+%3C=+5%2F3
-2.67%2F-1+%3C=+-m%2F-1+%3C=+1.67%2F-1
-1.67+%3C=+m+%3C=2.67+
solution set:
+graph%28+600%2C+600%2C+-5%2C+5%2C+-5%2C+5%2C+-1.67+%3C=+x+%3C=2.67%29+
(-1.67,2.67)


Graphs/692801: determine the point of intersection of:
a) 1/2(x-2)-1/4(3-y) ≥ 2
3x-4y ≥ 2
b) x-3(y-3) ≤ 3
2x - 1/3(3-3y) ≥ 4
x + 5/3y ≥ 1
1 solutions

Answer 427102 by MathLover1(6638) About Me  on 2012-12-11 10:14:09 (Show Source):
You can put this solution on YOUR website!
a)
1%2F2%28x-2%29-1%2F4%283-y%29+%3E=+2
3x-4y+%3E=+2
_________________
x%2F2-2%2F2-3%2F4-y%2F4+%3E=+2

4x%2F2-4%2A2%2F2-4%2A3%2F4-4%2Ay%2F4+%3E=+2%2A4
2x-4-3-y+%3E=+8
2x-4-3-8+%3E=+y
2x-15+%3E=+y
y%3C=2x-15


3x-4y+%3E=+2
3x-2+%3E=+4y
%283%2F4%29x-1%2F2+%3E=+y
y%3C=%283%2F4%29x-1%2F2
first graph both lines as y=2x-15 and y=%283%2F4%29x-1%2F2, find x and y-intercept and find intersection point
y=2x-15...set x=0 and find y
y=2%2A0-15........=>.........y=-15; y-intercept is at (0,-15)

y=2x-15...set y=0 and find x
0=2x-15........=>....x=15%2F2=>....x=7.5; x-intercept is at (7.5,0)
--
y=%283%2F4%29x-1%2F2...set x=0 and find y
y=%283%2F4%290-1%2F2........=>.........y=-1%2F2; y-intercept is at (0,-1%2F2)

y=%283%2F4%29x-1%2F2...set y=0 and find x
0=%283%2F4%29x-1%2F2........=>....%283%2F4%29x=1%2F2=>....x=%281%2F2%29%2F%283%2F4%29=4%2F6=2%2F3; x-intercept is at (2%2F3,0)
draw a lines, note both of them are a part of solution
+graph%28+600%2C+600%2C+-10%2C+20%2C+-20%2C+20%2C%283%2F4%29x-1%2F2%2C+2x-15%29+
now shade the part where y%3C=2x-15 and y%3C=%283%2F4%29x-1%2F2


b)
do same with these inequalities

+x-3%28y-3%29+%3E=+3....=>...+x-3y-9+%3E=+3=>...+x-3-9+%3E=+3y=>...+x-12+%3E=+3y...=>...%281%2F3%29+x-4+%3E=y...=>...y%3C=%281%2F3%29+x-4

2x+-+1%2F3%283-3y%29+%3E=+4..=>..2x-1-y+%3E=+4..=>..2x-1-4+%3E=+y..=>..2x-5%3E=+y..=>..y%3C=2x-5

+x+%2B+5%2F3y+%3E=+1...=>...+3x+%2B+5y+%3E=+3...=>...5y%3E=-3x%2B3..=>...y%3E=-%283%2F5%29x%2B3%2F5
same way you find x and y-intercepts and draw a lines than shade the area that belongs to a solution ; it will look like this:




expressions/691851: 16^(5/4)
1 solutions

Answer 426869 by MathLover1(6638) About Me  on 2012-12-09 15:03:08 (Show Source):
You can put this solution on YOUR website!
+16%5E%285%2F4%29

=root%284%2C+16%5E5%29.......write 16%5E5 as 16%5E4%2A16

=root%284%2C+16%5E4%2A16%29.............since root%284%2C16%5E4%29=16, we have

=16root%284%2C+16%29......write 16 as 2%5E4

=16root%284%2C+2%5E4%29..........since root%284%2C2%5E4%29=2, we have

=16%2A2

=32


Inequalities/691835: Use the multiplication property of inequalities to solve the inequality.
7/8x > -9/16

1 solutions

Answer 426865 by MathLover1(6638) About Me  on 2012-12-09 14:54:03 (Show Source):
You can put this solution on YOUR website!

7%2F8x+%3E+-9%2F16...cross multiply
7%2A16+%3E+-9%2A8x
112%3E+-72x
112%2F-72%3Ex
x%3C-1.5555555555555555555555555555556
x%3C-1.6


Functions/691755: What is the intercept form of y+6=2(x+2)
1 solutions

Answer 426837 by MathLover1(6638) About Me  on 2012-12-09 11:55:52 (Show Source):
You can put this solution on YOUR website!

the slope-intercept form: y=mx%2Bb
y%2B6=2%28x%2B2%29...solve for y
y=2%28x%2B2%29-6
y=2x%2B4-6
highlight%28y=2x-2%29......the slope-intercept form where the slope is m=2 and y-intercept is b=-2