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Functions/255552: what is the domain of the function f(x)=sqrt of x^2-3x-10?
1 solutions
Answer 187853 by edjones(7569)   on 2010-01-11 10:17:28 (Show Source):
You can put this solution on YOUR website!y=sqrt of x^2-3x-10
x^2-3x-10 cannot be negative because the sqrt of a negative number is not real.
So x^2-3x-10>=0
x^2-3x-10=0
(x-5)(x+2)=0
x=5, x=-2
Now we have to test on either side of 5 and -2 to see when y is >=0
x=-5: y=25+15-10=30
x=0: y=-10
x=10 y=100-30-10=60
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Domain is X (-infinity, -2] U [5,infinity)
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Ed
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Permutations/255633: computer with an old processor locks up if more than 4 application are running. 20 applications stored in program file. how many different sets of 4 can run
1 solutions
Answer 187845 by edjones(7569) on 2010-01-11 09:37:25 (Show Source):
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Probability-and-statistics/255295: what is the problability of getting all four problems right on a test with 4 differnet possible answers? what is the problability of getting at least one problem rgiht?
for my formula i got n=4 x=4 p=1 and q=0 for the first question and then n=4 x=1 p=1 and q= 3 for the second question
and the formula is n!/(n-x)!x!* p^x*q^n-x
1 solutions
Answer 187593 by edjones(7569) on 2010-01-10 12:17:31 (Show Source):
You can put this solution on YOUR website!what is the problability of getting all four problems right on a test with 4 differnet possible answers? what is the problability of getting at least one problem rgiht?
...IF YOU GUESS! You left this part out. Be sure to put it in next time.
Expansion of (c+w)^4 gives all the probabilities.
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a)
Let c=probability of guessing correctly =.25
w= prob. of guessing wrongly=.75
c^4=.25^4=.0039
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b)
1-w^4 One minus prob. that all are wrong.
=1-.75^4
=1-.3164
=.6836
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Ed
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Miscellaneous_Word_Problems/255211: team A and team B build houses.If the teams work together they can build a house in 4 days. Team A working alone can complete a house in 10 days.If the team works together for 3 days, but then team B Leaves, how much longer will team A need to finish the house? yuck!
1 solutions
Answer 187509 by edjones(7569) on 2010-01-10 01:21:26 (Show Source):
You can put this solution on YOUR website!Yuk? Roll up your sleeves, we've got work to do!
Together they do 1/4 the job in 1 day.
A does 1/10 job in 1 day.
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Together the do 3/4 the job in 3 days.
There is 1/4 of the job left to do. How many 1/10 make 1/4? Let a=number of days left.
a/10=1/4
a=10/4=5/2=2.5 days for team A to finish the job.
Easy, no ifs, ands or yuks about it.
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Ed
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Graphs/255183: find the domain of the function.
g(x)=9/10-9x
9/10-9 is a fraction
1 solutions
Answer 187508 by edjones(7569) on 2010-01-10 01:00:16 (Show Source):
You can put this solution on YOUR website!g(x)=9/(10-9x)
.
Division by zero is not allowed. When x=what will the denominator=0?
10-9x=0
-9x=-10
x=10/9
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The domain is all real numbers except x=10/9.
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Ed
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Polygons/255152: What regular polygon has an interior angle measure to exterior angle measure ratio of 3:1?
1 solutions
Answer 187506 by edjones(7569) on 2010-01-10 00:52:47 (Show Source):
You can put this solution on YOUR website!3x+x=180
4x=180
x=45
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The interior angle=45*3=135
Let n=number of sides.
Int. angle=(180(n-2))/n
(180(n-2))/n=135
180n-360=135n
45n=360
n=8
Octagon.
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Ed
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Rate-of-work-word-problems/254947: A swimming pool is 1 meters deep, 6 meters wide, and 30 meters long. Water is pumped into the pool at a rate of 100 liters per minute. How many hours will it take to fill the pool? (Remember that there are 1000 liters in a cubic meter).
1 solutions
Answer 187269 by edjones(7569) on 2010-01-08 19:21:14 (Show Source):
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Money_Word_Problems/254921: Company has a contract to sell 10,000 parts. Each part will sell for $45.50 apiece. There is a 20% probability that expeses will be $40,000 and an 80% probability that expenses will be $50,000. What is the expected pretax income for the firm's sales?
1 solutions
Answer 187235 by edjones(7569) on 2010-01-08 16:43:13 (Show Source):
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Probability-and-statistics/254938: John and Jane are married. The probability than John watches a certain television show is 0.4. The probability that Jane watches the show is 0.5. The probability that John watches the show, given that Jane does, is 0.7.
a) find the probability that both John and Jane watch the show.
b) find the probability that Jane watches the show, given that John does.
c) do John and Jane watch the show independently of each other? Justify your answer.
I tried the set with
{ WW, WD, DW, DD} with W being 'watched' and D standing for 'did not watch.'
It came out that a was 1/2 x 1/2 = .25
I also tried multiplying the probabilities together and got 0.20/25 = .8
That was for a. B would be .7/5 or .7 x .5 = .35. Is that even correct?
I say they could watch it independently of each other if there were other factors, but since they aren't part of the equation, I would say no.
Could you sort of give me a nudge?
1 solutions
Answer 187234 by edjones(7569) on 2010-01-08 16:36:50 (Show Source):
You can put this solution on YOUR website!j=probability john watches
m= probability jane watches
.
Check the Venn diagram below
.
.
Lets take a weekly show for 10 weeks. j watches 4 shows and m watches 5 in that period. The probability that John watches the show, given that Jane does, is 0.7 This means that while m is watching one of her five shows j is also watching .7 of the time so he is watching 5*.7=3.5 shows. That leaves him only 0.5 shows to watch on his own.
Now we divide the above numbers by 10 and do the Venn diagram. Put .05 in the red circle, .15 in the green circle and .35 in the intersection between the circles and .45 outside the circles for when nobody is watching the show so that the sum equals 1
.
a) .35 the intersection.
b) .35/.4=.875
c) Yes. .05 for j and 1.5 for m
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E-mail me any more questions.
This is a tough one. Let me know if it is correct or not.
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Ed
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Inequalities/254931: ok the problem is 5/x is >= -1
i'm not sure how the book got the graph to long how it does
i only get one section that is shaded and they have two
1 solutions
Answer 187221 by edjones(7569) on 2010-01-08 15:51:42 (Show Source):
You can put this solution on YOUR website!5/x >= -1
.
This is a rational inequality.
We have to find the zeros of the numerator and undefined parts from the denominator.
5-5=0 so -5 is the zero of the numerator
when x=0 then the inequality is undefined.
.
Now we have to test on either side of -5 and x=0:
x=-6 5/-6=-5/6 which is >-1
x=-1 5/-1=-5 which is <-1
x=1 5/1=5 which is >-1
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-5=>x>0 or (-infinity, -5] U (0.infinity)
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Ed
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Circles/254908: An equilateral triangle is inscribed in a circle with a radius of 6". Find the area of the segment cut off by one side of the triangle
1 solutions
Answer 187216 by edjones(7569) on 2010-01-08 15:14:57 (Show Source):
You can put this solution on YOUR website!
| Solved by pluggable solver: Calculate side length of equilateral triangle inscribed in the circle |
The circle of radius 6 with center O with an equilateral triangle ABC inscribed in it.
Join edges A,B and C with center O as shown in figure.
Consider Triangle AOB and AOC,
1.>  .............(Sides of Equilateral triangle are equal)
2.> .............(These are radius of a circle)
3.>OA is common side to both Triangles.
From conditions 1,2 and 3
Triangle AOB and AOC are congruent to each other. (SSS congruency condition)
Now since triangles are congruent,
Therefore,  ...............(4)
Similarly,  ...............(5)
As, Angle CAB is an angle in a equilateral triangle
Hence,  degrees ...............(6)
Now, 
 ..........(From (4))
 degrees
 degrees ...........(6)
Similarly, 
and from condition 5,  degrees ...........(7)
Now consider Triangle AOB,
Sum of angles in a Triangle is 180 degrees.
Hence, 
 ........(From 6 and 7)
 ...........(8)
In Triangle AOB using sine rule,
Hence the side of an equilateral triangle inscribed in a circle of radius 6 is 10.3923048.
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A(equilateral triangle)=s^2sqrt(3)/4
(10.39^2*sqrt(3))/4
=46.74 sq in
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A(circle)=pi*r^2
=pi*6^2
=113.1 sq in
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113.1-46.74=66.35 area of all 3 segments cut off by a side of the triangle.
66.35/3
=22.12 sq in, area of the segment cut off by one side of the triangle.
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Ed
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Linear-equations/254877:
(1)
Which of the folowing functions has its vertex below the x-axis?
f(x)= (x-7)^2
f(x)= x^2-8
f(x)= 2x^2
f(x)= (x+3)^2
(2)
Find the minimum or maximum value of f(x)=x^2-2x-6 Then state the domain and range of the function.
Answer
The maximum value is 1. D: {all real numbers}; R: {y | y –7}
The maximum value is 1. D: {x | x –7 }; R: {all real numbers}
The minimum value is –7. D: {all real numbers}; R: {y | y –7}
The minimum value is –7. D: {x | x –7 }; R: {all real numbers}
(3)
A toy rocket is launched from the ground level with an initial vertical velocity of 96 ft/s. After how many seconds will the rocket hit the ground?
Answer
6 seconds
0 seconds or 6 seconds
0 seconds
square root of 6 seconds
1 solutions
Answer 187207 by edjones(7569) on 2010-01-08 14:31:57 (Show Source):
You can put this solution on YOUR website!2)
f(x)=a^2+bx+c
x^2-2x-6
a is positive so there is a minimum.
minimum at x=-b/2a=2/2=1
minimum at y=1-2-6=-7
Domain is all real numbers
Range is [-7, infinity)
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Ed
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Equations/254900: F(x)= x^3-5x^2+144x-720
I got one of the zeroes (x=5) I need the other 2... they should be imaginary numbers.
1 solutions
Answer 187192 by edjones(7569) on 2010-01-08 13:57:47 (Show Source):
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Inequalities/254893: I'm a little lost on how to solve this problem.
Solve the rational inequality 3x-1/x-8 ≤ 0
1 solutions
Answer 187189 by edjones(7569) on 2010-01-08 13:47:22 (Show Source):
You can put this solution on YOUR website!3x-1/x-8 ≤ 0
This is a rational inequality.
We have to find the zeros of the numerator and undefined parts from the denominator.
3x-1=0
3x=1
x=1/3
.
when x=8 then x-8 = 0 and the inequality is undefined.
Now we test points larger and smaller than 1/3 and 8 to see if the fraction is <= 0
x=0: -1/-8=1/8 is >0
x=1: 3-1/1-8=2/-7=-2/7 is <0
x=10 30-1/10-8=29/2 is >0
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1/3<=x<8 or x[1/3, 8)
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Ed
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