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lwsshak3 answered: 6492 problems
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Rational-functions/686232: Please help rationalize the problem below with brief step-by-step explanation. Thank you in advance for your time and assistance!
(2)/(3t)^(1/2) 1 solutions
Answer 424721 by lwsshak3(6494) on 2012-11-28 00:19:38 (Show Source):
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test/686223: Find the value of k so that the three points lie on the same line. Write the equation in point slope form. The points given are (1,-2) (-2,4) (4,k) 1 solutions
Answer 424720 by lwsshak3(6494) on 2012-11-28 00:11:58 (Show Source):
You can put this solution on YOUR website!Find the value of k so that the three points lie on the same line. Write the equation in point slope form. The points given are (1,-2) (-2,4) (4,k)
**
y-y1=m(x-x1)
using given point (1,-2)
y-(-2)=m(x-1)
y+2=m(x-1)
using given points (1,-2) and (-2,4) to find slope,m
m=∆y/∆x=(4-(-2))/(-2-1)=(4+2)/-3=6/-3=-2
y+2=-2(x-1)
y+2=-2x+2
y=-2x
solving for k
k=-2*4=-8
k=-8
see graph below:
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Travel_Word_Problems/685928: you can travel 40 miles on motorcycle in the same time that it takes to travel 15 miles on bicycle. if your motorcycle's rate is 20 miles per hour faster than your bicycle's, fine the average rate for each 1 solutions
Answer 424657 by lwsshak3(6494) on 2012-11-27 16:32:22 (Show Source):
You can put this solution on YOUR website!you can travel 40 miles on motorcycle in the same time that it takes to travel 15 miles on bicycle. if your motorcycle's rate is 20 miles per hour faster than your bicycle's, fine the average rate for each
let x=rate of speed of bicycle
x+20=rate of speed of motorcycle
travel time= distance/rate of speed (same for both)
40/(x+20)=15/x
40x=15(x+20
40x=15x+300
25x=300
x=12
x+20=32
rate of speed of bicycle=12 mph
rate of speed of motorcycle=32 mph
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Expressions-with-variables/685894: Find an equation of the line passing (-7,2) and (4,5) 1 solutions
Answer 424649 by lwsshak3(6494) on 2012-11-27 16:19:52 (Show Source):
You can put this solution on YOUR website!Find an equation of the line passing (-7,2) and (4,5)
Equation of a line: y=mx+b, m=slope, b=y-intercept
For given problem:
m=∆y/∆x=(5-2)/(4-(-7))=3/11
equation: y=3x/11+b
solve for b using one of given coordinates(4,5)
5=3*4/11+b
b=5-12/11
b=55/11-12/11=43/11
equation: y=3x/11+43/11
see graph below:
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Quadratic_Equations/685893: Please help me with this question. I'm getting really confused with the 3x. I' not sure where to start.
Find all of the exact solutions to the following equation. (Use the parameter k as necessary to represent any integer.)
cos(3x) =1/2
1 solutions
Answer 424643 by lwsshak3(6494) on 2012-11-27 16:04:57 (Show Source):
You can put this solution on YOUR website!Find all of the exact solutions to the following equation. (Use the parameter k as necessary to represent any integer.)
cos(3x) =1/2
3x=π/3+2πk, 5π/3+2πk, k=any integer
x=π/9+2πk, 5π/9+2πk, k=any integer
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Exponential-and-logarithmic-functions/685808: Solve the following exponential equation. Exact answers only.
49^x-12*7^x=-36
I have tried and tried on this problem. I do not understand. I would appreciate help on this! Thank you! 1 solutions
Answer 424637 by lwsshak3(6494) on 2012-11-27 15:57:15 (Show Source):
You can put this solution on YOUR website!Solve the following exponential equation. Exact answers only.
49^x-12*7^x=-36
7^2x-12*7^x=-36
let u=7^x
u^2=7^2x
u^2-12u+36=0
(u-6)(u-6)=0
u=6=7^x
6=7^x
log6=xlog7
x=log6/log7
x≈.9208..
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Geometry_Word_Problems/685869: In an isosceles triangle, the base is 7 more than one-half times the legs. If perimeter is 22 centimeters. Find length of each leg. 1 solutions
Answer 424619 by lwsshak3(6494) on 2012-11-27 14:57:23 (Show Source):
You can put this solution on YOUR website!In an isosceles triangle, the base is 7 more than one-half times the legs. If perimeter is 22 centimeters. Find length of each leg.
**
let x=length of each leg
base+2 legs=perimeter
(1/2)x+7+2x=22
x/2+7+2x=22
5x/2=15
5x=30
x=6
length of each leg=6 cm
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logarithm/685867: I need help solving this question.
write the following as a single logarithm with coefficient of 1. please show steps. thanks in adavance
3logc(x^4)-2logc(3x)
1 solutions
Answer 424614 by lwsshak3(6494) on 2012-11-27 14:48:21 (Show Source):
You can put this solution on YOUR website!write the following as a single logarithm with coefficient of 1. please show steps. thanks in adavance
3logc(x^4)-2logc(3x)
logc[(x^4)^3/(3x)^2]
logc[(x^12/(9x^2]
logc[(x^10/9)]
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Length-and-distance/685863: Two cars leave towns 640 kilometers apart at the same time and travel toward each other. One car's rate is 10 kilometers per hour more than the other's. If they meet in 4 hours, what is the rate of the faster car? 1 solutions
Answer 424612 by lwsshak3(6494) on 2012-11-27 14:44:54 (Show Source):
You can put this solution on YOUR website!Two cars leave towns 640 kilometers apart at the same time and travel toward each other. One car's rate is 10 kilometers per hour more than the other's. If they meet in 4 hours, what is the rate of the faster car?
**
let x=rate of speed of faster car
x-10=rate of speed of slower car
distance=rate of speed*travel time
4x+4(x-10)=640
4x+4x-40=640
8x=680
x=85
rate of speed of faster car= 85km/hr
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Mixture_Word_Problems/685848: A metal alloy weighing 12 lb. and containing
20% copper is melted and mixed with 3 lb. of a
different alloy which contains 40% copper.
What percent of the resulting alloy is copper? 1 solutions
Answer 424609 by lwsshak3(6494) on 2012-11-27 14:35:43 (Show Source):
You can put this solution on YOUR website!A metal alloy weighing 12 lb. and containing
20% copper is melted and mixed with 3 lb. of a
different alloy which contains 40% copper.
What percent of the resulting alloy is copper?
**
20%*12+40%*3/12+3=(2.4+1.2)/15=3.6/15=.24
What percent of the resulting alloy is copper? 24%
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logarithm/685036: Solve the logarithmic equation algebraically.Approximate the result to three decimal places.
log(4x)-log(14+the square root of x)=2 1 solutions
Answer 424513 by lwsshak3(6494) on 2012-11-27 02:44:35 (Show Source):
You can put this solution on YOUR website!Solve the logarithmic equation algebraically.Approximate the result to three decimal places.
log(4x)-log(14+the square root of x)=2
**
log(4x)-log(14+√x)=2
log[4x/(14+x^(1/2))=2
convert to exponential form
10^2=4x/(14+x^(1/2))=100
4x=1400+100x^(1/2)
4x-1400-100x^(1/2)=0
let u=x^(1/2)
u^2=x
4u^2-100u-1400=0
u^2-25u-350=0
(u-35)(u+10)
u=35=√x
x=35^2=1225
or
u=-10=√x
x=(-10)^2=100
ans:
x=1225
or
x=100
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logarithm/685594: Solve each exponential equation for x. Give an exact solution and also approximate the solution to four decimals
a). 4^(3x+2)=9
b). 5^(3x-5)=4 1 solutions
Answer 424508 by lwsshak3(6494) on 2012-11-27 01:56:21 (Show Source):
You can put this solution on YOUR website!Solve each exponential equation for x. Give an exact solution and also approximate the solution to four decimals
a). 4^(3x+2)=9
(3x+2)log4=log9
(3x+2)=log9/log4
3x=(log9/log4)-2
x=[(log9/log4)-2]/3 (exact solution)
x=-0.1383..
..
b). 5^(3x-5)=4
(3x-5)log5=log4
3x-5=log4/log5
x=[(log4/log5)+5]/3 (exact solution)
x=1.9538..
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logarithm/685595: Find all the real number roots of the equation.
log2(x+7)-log2(x-3)=3 1 solutions
Answer 424507 by lwsshak3(6494) on 2012-11-27 01:38:20 (Show Source):
You can put this solution on YOUR website!Find all the real number roots of the equation.
log2(x+7)-log2(x-3)=3
log2[(x+7)/(x-3)]=3
convert to exponential form
(x+7)/(x-3)=2^3=8
x+7=8x-24
7x=31
x=31/7=4.4286..
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logarithm/685597: Solve each exponential equation for x. Give an exact solution and also approximate the solution to four decimals
2*5^(x-1)=1 1 solutions
Answer 424505 by lwsshak3(6494) on 2012-11-27 01:19:57 (Show Source):
You can put this solution on YOUR website!Solve each exponential equation for x. Give an exact solution and also approximate the solution to four decimals
2*5^(x-1)=1
log2+(x-1)log5=log1
log1=0
log2+(x-1)log5=0
log2+(x-1)log5=-log2
x-1=-log2/log5
x=(-log2/log5)+1 (exact solution)
x=0.5963..
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logarithm/685605: randy invested his inheritance in an account that paid 6.9% interest, coupounded continuously. after 5 years, he found that he now had $52,565.56. what was the orginal amount of his inheritance?
1 solutions
Answer 424504 by lwsshak3(6494) on 2012-11-27 01:09:00 (Show Source):
You can put this solution on YOUR website!randy invested his inheritance in an account that paid 6.9% interest, coupounded continuously. after 5 years, he found that he now had $52,565.56. what was the orginal amount of his inheritance?
**
Formula for continuous compounding:A= Pe^rt, P=initial investment, r=rate of interest, A=amt after t years
52565.56=Pe^(.069*5)=Pe^.345
P=52565.56/e^.345=37228
orginal amount of his inheritance=$37,228.00..
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Quadratic-relations-and-conic-sections/684975: E is the ellipse with foci at (4,-2) and (4,8) and whose major axis has length of 20
Find an equation for the indicated conic section 1 solutions
Answer 424503 by lwsshak3(6494) on 2012-11-27 00:50:05 (Show Source):
You can put this solution on YOUR website!E is the ellipse with foci at (4,-2) and (4,8) and whose major axis has length of 20
Find an equation for the indicated conic section
**
This is an ellipse with vertical major axis.
Its standard form of equation:  , a>b, (h,k)=(x,y) coordinates of center
For given ellipse:
center: (4,3)
given length of vertical major axis=20=2a
a=10
a^2=100
c=5 (distance from center to foci)
c^2=25
c^2=a^2-b^2
b^2=a^2-c^2=100-25=75
Equation of given ellipse:
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Trigonometry-basics/685106: Find the exact values of each trigonometric function at 0(theta)=-(7pi/12). For sin cos and tan. 1 solutions
Answer 424398 by lwsshak3(6494) on 2012-11-26 16:47:50 (Show Source):
You can put this solution on YOUR website!Find the exact values of each trigonometric function at 0(theta)=-(7pi/12). For sin cos and tan.
-(7π/12) is in quadrant III where sin<0, cos<0, tan>0
-(7π/12)=[(-3π/12)+(-4π/12)]=[(-π/4)+(-π/3)]
sin-(7π/12)=sin[(-π/4)+(-π/3)]=[sin(-π/4)cos(-π/3)]+[cos(-π/4)sin(-π/3)]
=[(-√2/2)*(1/2)+√2/2*-√3/2]
=[-√2/4-√6/4]
=(-√2-√6)/4
sin-(7π/12)=-(√2+√6)/4
check with calculator:
sin-(7π/12)=-0.9659..
-(√2+√6)/4=-0.9659..
..
cos-(7π/12)=cos[(-π/4)+(-π/3)]=[cos(-π/4)cos(-π/3)]-[sin(-π/4)sin(-π/3)]
=[(√2/2)*(1/2)]-[-√2/2*-√3/2]
=[√2/4-√6/4]
=(√2-√6)/4
check with calculator:
cos-(7π/12)=-0.2588..
(√2-√6)/4=-0.2588..
..
tan-(7π/12)=tan[(-3π/12)+(-4π/12)]=tan[(-π/4)+(-π/3)]
=[tan(-π/4)+tan(-π/3)]/[1-tan(-π/4)*tan(-π/3)]=[-1+(-√3)]/[1-(-1*(-√3)]
=(-1-√3)/(1-√3)
check with calculator:
tan-(7π/12)=3.732..
(-1-√3)/(1-√3)=3.732..
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Trigonometry-basics/685120: Given that sin(3θ)= (1/5) and (π/2)<3θ<π: Find cos(3θ), sin(6θ), and tan (3θ/2) 1 solutions
Answer 424388 by lwsshak3(6494) on 2012-11-26 14:54:31 (Show Source):
You can put this solution on YOUR website!Given that sin(3θ)= (1/5) and (π/2)<3θ<π: Find cos(3θ), sin(6θ), and tan (3θ/2)
You are working with reference angle 3θ in quadrant II where sin>0, cos<0, and tan<0
sin3θ=opposite side/hypotenuse=1/5
adjacent side=√(5^2-1^2)=√(25-1)=√24
..
cos(3θ)=-√24/5
..
Identity: sin 2s=2sins cos s
sin(6θ)=2sin3θcos3θ
=2*1/5*-√24/5
=-(2√24)/25
..
Identity: tan s/2= (sin s)/(1+cos s)
tan (3θ/2)=sin3θ/1+cos3θ
=(1/5)/(1-√24/5)
=(1/5)/(5-√24)/5
=1/(5-√24)
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Trigonometry-basics/685127: Solve each equation on the interval (0,2pi): a.) 2sin^(2)x-cos x-1=0, b.) sin 3x cos 2x + cos3x sin2x= (√2/2). 1 solutions
Answer 424381 by lwsshak3(6494) on 2012-11-26 14:22:31 (Show Source):
You can put this solution on YOUR website!Solve each equation on the interval (0,2pi): a.) 2sin^(2)x-cos x-1=0, b.) sin 3x cos 2x + cos3x sin2x= (√2/2).
**
a.) 2sin^(2)x-cosx-1=0
2(1-cos^2x)-cosx-1=0
2-2cos^2x-cosx-1=0
2cos^2x+cosx-1=0
(2cosx-1)(cosx+1)=0
2cosx-1=0
cosx=1/2
x=π/3, 5π/3
or
cosx+1=0
cosx=-1
x=π
..
b.) sin 3x cos 2x + cos3x sin2x= (√2/2).
Identity:sin(s+t)=sin s cos t+cos s sin t
sin 3x cos 2x + cos3x sin2x= (√2/2)
sin(3x+2x)=sin(5x)=√2/2
5x=π/4, 3π/4
x=π/20, 3π/20
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logarithm/684125: How would I find the inverse of f(x)=log 9 (x)? Does having the parenthesis around x change it?
Here is what I did:1) re-write it as y=log 9 (x); 2) identify 9 as the base, y as the exponent, and keeping x on the right side of the equation; 3) re-write it as 9^y=x. 1 solutions
Answer 423995 by lwsshak3(6494) on 2012-11-24 03:01:25 (Show Source):
You can put this solution on YOUR website!The inverse of the log function is the exponential form:
For given problem:y=log 9 (x)
Exponential form: base(9) raised to log of number(y)=number(x)
9^y=x
so, you were right on.
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logarithm/684219: Please help me solve this:
Write as a single logarithm:
1/3[logsubscript4x-logsubscript4y] + 2logsubscript4(3x-4)
1 solutions
Answer 423992 by lwsshak3(6494) on 2012-11-24 02:48:13 (Show Source):
You can put this solution on YOUR website!Write as a single logarithm:
1/3[logsubscript4x-logsubscript4y] + 2logsubscript4(3x-4)
1/3[log4(x)-log4(y)]+2log4(3x-4)
log4[(x/y)^(1/3)*(3x-4)^2]
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Trigonometry-basics/683726: Write the expression as the sine, cosine, or tangent of an angle.
sin 48° cos 15° - cos 48° sin 15°
And also:
Find all solutions to the equation.
cos x = sin x
And:
Verify the identity.
4 csc 2x = 2 csc2x tan x
1 solutions
Answer 423991 by lwsshak3(6494) on 2012-11-24 02:34:42 (Show Source):
You can put this solution on YOUR website!Write the expression as the sine, cosine, or tangent of an angle.
sin 48° cos 15° - cos 48° sin 15°
Identity: sin(s-t)=sin s cos t-cos s sin t
sin 48° cos 15° - cos 48° sin 15°=sin(48º-15º)=sin 33º
..
And also:
Find all solutions to the equation.
cos x = sin x
tan x=cos x/sin x=1
x=45º+360ºk, x=225º+360ºk, k=integer
..
And:
Verify the identity.
4 csc(2x) = 2 csc^2x tan x
start with right side
2csc^2x tanx
=2/sin^2x*sinx/cosx
=2/sinx cosx
multiply top and bottom by 2
=4/2sinx cosx
=4/sin(2x)
=4csc(2x)
verified: right side=left side
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Travel_Word_Problems/683843: A man drove 156 km at a constant rate. If he had driven 5km/hr. faster he would made the trip in 12 minutes less time. How fast did he drive?
ans. 60 KPH
help me with solution pls.. 1 solutions
Answer 423769 by lwsshak3(6494) on 2012-11-22 02:35:22 (Show Source):
You can put this solution on YOUR website!A man drove 156 km at a constant rate. If he had driven 5km/hr. faster he would made the trip in 12 minutes less time. How fast did he drive?
ans. 60 KPH
**
let x=how fast he drove
x+5=speed in 12 min less time
156/x-156/(x+5)=12 min=12/60 hr=0.2 hr
156/x-156/(x+5)=.2
LCD: x(x+5)
156(x+5)+156x=x(x+5)(.2)
156x+780+156x=.2x^2+x
.2x^2+x-780=0
2x+10x-7800=0
x+5x-3900=0
(x+65)(x-60)=0
x+65=0
x=-65(reject, x>0)
or
x-60=0
x=60
how fast he drove=60 km/hr
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logarithm/683829: 2. Solve the following exponential equation. Exact answers only.
49^x-12*7^x=-36 1 solutions
Answer 423766 by lwsshak3(6494) on 2012-11-22 01:37:41 (Show Source):
You can put this solution on YOUR website!2. Solve the following exponential equation. Exact answers only.
49^x-12*7^x=-36
7^2x-12*7^x+36=0
let u=7^x
u^2=7^2x
u^2-12u+36=0
(u-6)(u-6)=0
u=6=7^x
xlog7=log6
x=log6/log7
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