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lwsshak3 answered: 6520 problems
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Quadratic-relations-and-conic-sections/683687: Write an equation for the ellipse
Eccentricity 3/4; foci (0,-2) (0,2) 1 solutions
Answer 423762 by lwsshak3(6522) on 2012-11-22 00:15:13 (Show Source):
You can put this solution on YOUR website!Write an equation for the ellipse
Eccentricity 3/4; foci (0,-2) (0,2)
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: (0,0)
c=2 (center to focus)
c^2=4
eccentricity:=3/4=c/a
a=4c/3=16/3
a^2=256/9
c^2=a^2-b^2
b^2=a^2-c^2=256/9-4=256/9-36/9=220/9
Equation:
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Quadratic-relations-and-conic-sections/683786: graph the parabola with the following equation.. Give the focus coordinates, vertex coordinates, equation of directrix and one additional point on the curve..
The equation is:
x= 1/16y^2 1 solutions
Answer 423718 by lwsshak3(6522) on 2012-11-21 20:12:36 (Show Source):
You can put this solution on YOUR website!graph the parabola with the following equation.. Give the focus coordinates, vertex coordinates, equation of directrix and one additional point on the curve..
The equation is:
x= 1/16y^2
**
rewrite equation:
y^2=16x
This is a parabola that opens rightwards.
Its standard form: (y-k)^2=4p(x-h), (h,k)=coordinates of the vertex
For given equation: y^2=16x
vertex: (0,0)
axis of symmetry: y=0
4p=16
p=4
focus=(4,0) (p-distance right of vertex on axis of symmetry)
directrix: x=4 ( (p-distance left of vertex on axis of symmetry)
2 points on curve: (1,4) and (1,-4)
see graph below:
y=(16x)^.5
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Trigonometry-basics/682705: Use a half-angle formula to find the exact value of sin ((3pi)/8)
Thanks!! 1 solutions
Answer 423611 by lwsshak3(6522) on 2012-11-21 02:54:01 (Show Source):
You can put this solution on YOUR website!Use a half-angle formula to find the exact value of sin ((3pi)/8)
Identity:sin(s/2)=±√[(1-cos s)/2]
sin(3π/8)=sin[(3π/4)/2]=√[1-cos(3π/4)/2]=√[1-(-√2/2)/2]=√[(1+√2/2)/2]
sin(3π/8)=√[(1+√2/2)/2]
check with calculator:
sin(3π/8)≈.9238..
√[(1+√2/2)/2]≈.9238..
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Trigonometry-basics/683216: IF (-4,6) is on the terminal side of theta what are the 6 trig functions. 1 solutions
Answer 423608 by lwsshak3(6522) on 2012-11-21 01:40:58 (Show Source):
You can put this solution on YOUR website!IF (-4,6) is on the terminal side of theta what are the 6 trig functions.
visualize a circle with center at (0,0) where a point on the circle is at (-4,6)
This gives a right triangle where the x-coordinate(-4) is the adjacent side and y-coordinate(6) is the opposite sidee. The hypotenuse then=√(4^2+6^2)=√(16+36)=√52
6 trig functions as follows:
sin=6/√52
cos=-4/√52
tan=-6/4
csc=√52/6
sec=-√52/4
cot=-4/6
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Trigonometry-basics/683542: Find all solutions of the equation cos2x + cosx = 2 in the interval [0, 4pi] 1 solutions
Answer 423607 by lwsshak3(6522) on 2012-11-21 01:07:51 (Show Source):
You can put this solution on YOUR website!Find all solutions of the equation cos2x + cosx = 2 in the interval [0, 4pi]
cos2x + cosx = 2
2cos^2x-1+cosx=2
2cos^2x+cosx-3=0
(2cosx+3)(cosx-1)=0
2cosx+3=0
cosx=-3/2 (reject, -1≤cosx≤1)
or
cosx-1=0
cosx=1
x=0, 2π, 4π
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Trigonometry-basics/683395: Solve the given equation. (Enter your answers as a comma-separated list. Let k be any integer. Round terms to two decimal places where appropriate.)
sin theta = -0.4
1 solutions
Answer 423606 by lwsshak3(6522) on 2012-11-21 00:36:57 (Show Source):
You can put this solution on YOUR website!Solve the given equation. (Enter your answers as a comma-separated list. Let k be any integer. Round terms to two decimal places where appropriate.)
sin theta = -0.4
sinx=0.4
x≈0.41+2πk, 2.73+2πk, k=integer
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Trigonometry-basics/683396: Solve the equation for (x) over the interval [0(degrees),360(degrees)). What is the solution set?
1 solutions
Answer 423605 by lwsshak3(6522) on 2012-11-21 00:32:15 (Show Source):
You can put this solution on YOUR website!Solve the equation for (x) over the interval [0(degrees),360(degrees)). What is the solution set?2sin^2(x) = sqrt(3)sin(x)
2sin^2(x) =√3)sin(x)
2sin^2(x)-√3)sin(x=0
sinx(2sinx-√3)=0
sinx=0
x=0, 180º
or
2sinx-√3=0
sinx=√3/2
x=60º, 120º (in quadrants I and II where sin>0)
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Trigonometry-basics/683403: Solve the equation for (theta) over the interval [0(degrees),360(degrees)). If necessary, round your answers to the nearest tenth.
What is the solution set? 1 solutions
Answer 423604 by lwsshak3(6522) on 2012-11-21 00:17:26 (Show Source):
You can put this solution on YOUR website!Solve the equation for (theta) over the interval [0(degrees),360(degrees)). If necessary, round your answers to the nearest tenth.

3secx-2√3) = 0
secx=2√3/3
cosx=1/secx=3/(2√3)=√3/2
x=30º, 300º (in quadrants I and IV where cos>0)
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Trigonometry-basics/683501: Find the general solutions to the equation . List all solutions on the interval [0,4pi] 1 solutions
Answer 423603 by lwsshak3(6522) on 2012-11-21 00:08:42 (Show Source):
You can put this solution on YOUR website!List all solutions on the interval [0,4pi]
csc^2theta+6csc(theta)+5=0

(cscx+5)(cscx+1)=0
cscx+5=0
cscx=-5
sinx=1/cscx=-1/5
x≈3.343,6.081,9.626,12.635 (in quadrants III and IV where sin<0)
or
cscx+1=0
cscx=-1
sinx=1/cscx=-1
x=3π/2 and 7π/2
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Trigonometry-basics/683350: Solve the following, finding all solutions in radians in [0,2 )
2cos^2(x)-√(3)cos(x)=0 1 solutions
Answer 423550 by lwsshak3(6522) on 2012-11-20 17:35:35 (Show Source):
You can put this solution on YOUR website!Solve the following, finding all solutions in radians in [0,2)
2cos^2(x)-√(3)cos(x)=0
cosx(2cosx-√3)=0
cosx=0
x=π/2+2πk and 3π/2+2πk, k=integer
and
2cosx-√3=0
cosx=√3/2
x=π/6+2πk and 11π/6+2πk, k=integer (in quadrants I and IV where cos>0)
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Trigonometry-basics/683117: Please solve equation without using a calculator. Show all work
{{Cos(2sin^-1(1/4)}} 1 solutions
Answer 423477 by lwsshak3(6522) on 2012-11-20 02:50:58 (Show Source):
You can put this solution on YOUR website!Please solve equation without using a calculator. Show all work
{{Cos(2sin^-1(1/4)}}
sin^-1(1/4)=an angle x whose sin=1/4
Cos(2sin^-1(1/4)=cos2x
=1-2sin^2x=1-2*(1/4)^2
=1-(2/16)
=1-(1/8)
=7/8
check with calculator:
2sin^-1(1/4)≈.2527*2≈.5054
cos(.5054)≈.875=7/8
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Trigonometry-basics/683118: Please solve equation for x. Show all work. {{Arctanx=arccos5/13}}
1 solutions
Answer 423476 by lwsshak3(6522) on 2012-11-20 01:40:33 (Show Source):
You can put this solution on YOUR website!Please solve equation for x. Show all work. {{Arctanx=arccos5/13}}
arccos5/13=an angle whose cos=5/13=adjacent side/hypotenuse
opposite side=√(13^2-5^2)=√(169-25)=√144=12
tan=opposite side/adjacent side=12/5
Arctanx=to the same angle whose tan=x
x=12/5
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Trigonometry-basics/683120: Please solve equation in radians for all exact solutions. Show all work
{{2√3cos(x/2)=-3}} 1 solutions
Answer 423475 by lwsshak3(6522) on 2012-11-20 01:30:05 (Show Source):
You can put this solution on YOUR website!Please solve equation in radians for all exact solutions. Show all work
{{2√3cos(x/2)=-3}}
2√3cos(x/2)=-3
cos(x/2)=-3/(2√3)=-3√3/2*3=-√3/2
cos(x/2)=-√3/2
x/2=5π/6+2πk and 7π/6+2πk, k=integer (in quadrants II and III where cos<0)
x=5π/3+2πk and 7π/3+2πk, k=integer
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Trigonometry-basics/682943: I need help slove this identity, please show the steps becasue I subed in 2 for B and both sides were the same so I know it is an identity but I do not how to prove it without subing in a number
(1+2inBcosB)/(sinB+cosB)=sinB+cosB
Thanks :) 1 solutions
Answer 423473 by lwsshak3(6522) on 2012-11-20 01:07:07 (Show Source):
You can put this solution on YOUR website!prove following identity:
(1+2sinBcosB)/(sinB+cosB)=sinB+cosB
start with left side
(1+2sinBcosB)/(sinB+cosB)
multiply top and bottom by (sinB+cosB)
=(1+2inBcosB)/(sinB+cosB)* (sinB+cosB)/ (sinB+cosB)
=(1+2inBcosB)(sinB+cosB/ (sinB+cosB)/ (sinB+cosB)
=(1+2inBcosB)(sinB+cosB/ (sin^2B+2sinBcosB+cos^2B)
=(1+2inBcosB)(sinB+cosB/ (1+2sinBcosB)
=sinB+cosB
verified:
left side=right side
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Trigonometry-basics/682945: I need help sloving this identity, please show the steps becasue I subed in 2 for B and both sides were the same so I know it is an identity but I do not how to prove it without subing in a number
(1-cosB)/(sinB)=(sinB)/(1+cosB)
Thanks :) 1 solutions
Answer 423400 by lwsshak3(6522) on 2012-11-19 18:59:18 (Show Source):
You can put this solution on YOUR website!prove following identity:
(1-cosB)/(sinB)=(sinB)/(1+cosB)
stare with left side
(1-cosB)/(sinB)
multiply both top and bottom by 1+cosB, making the denominator a difference of 2 squares
(1-cosB)/(sinB)*1+cosB/1+cosB
=(1-cos^2B)/sinB(1+cosB)
=sin^2B/(sinB(1+cosB))
=sinB/1+cosB
verified: left side=right side
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Trigonometry-basics/682764: please help me solve this equation. Solve the equation for x over the interval [0,2pi) {{4cos2x=squareroot3}} 1 solutions
Answer 423350 by lwsshak3(6522) on 2012-11-19 16:09:30 (Show Source):
You can put this solution on YOUR website!please help me solve this equation. Solve the equation for x over the interval [0,2pi) {{4cos2x=squareroot3}}
4cos(2x)=√3
cos(2x)=√3/4
Identity: cos(2x)=1-2sin^2x
1-2sin^2x=√3/4
2sin^2x=1-√3/4=(4-√3)/4
sin^2x=(4-√3)/8≈.2835
sinx=√.2835=≈.5324
using calculator set to radians
x=0.5685 and 2.5801 (in Q1 and Q2 where sin>0)
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Trigonometry-basics/682779: solve the equation on the interval [0,2pi)
tan x = -3.5618
What is the solution set answered in radians and rounded to 4 decimal places
or
There is no solution 1 solutions
Answer 423348 by lwsshak3(6522) on 2012-11-19 15:48:07 (Show Source):
You can put this solution on YOUR website!solve the equation on the interval [0,2pi)
tan x = -3.5618
What is the solution set answered in radians and rounded to 4 decimal places
**
arctan(-3.5618)=1.8445 and 4.9681(in Q2 and Q4 where tan<0)
x=1.8445 and 4.9681
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Trigonometry-basics/682804: Find Approximate Values of theta between 0 degrees and 360 degrees that make the equation a true statement
Sec(theta)= -1.058
1 solutions
Answer 423344 by lwsshak3(6522) on 2012-11-19 15:19:10 (Show Source):
You can put this solution on YOUR website!Find Approximate Values of theta between 0 degrees and 360 degrees that make the equation a true statement
Sec(theta)= -1.058
cos(theta)=1/sec(theta)=-1/1.058≈-.945
using calculator
arccos(-.945)
theta≈161º and 199º (in Q2 and Q3 where cos<0)
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Trigonometry-basics/682406: Cot x + tan x = 2 csc2x
Prove the following is an identity.
Having a difficult time fitting the left side to equal the right.
I know that cot x= cos x/ sin x and tan x = sin x / cos x 1 solutions
Answer 423255 by lwsshak3(6522) on 2012-11-19 02:41:25 (Show Source):
You can put this solution on YOUR website!Cot x + tan x = 2 csc2x
Prove the following is an identity.
**
start with left side:
Cot x + tan x=cosx/sinx+sinx/cosx=(cos^2x+sin^2x)/sinx cosx
=1/sinx cosx=2/2sinx cosx=2/sin(2x)=2csc(2x)
verified:
left side=right side
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Trigonometry-basics/682513: Use a sum or difference formula to find the exact value of the trigonometric function
cos 75degree
simplyfy the answer including any radicals
use integers or fractions for any number in the expression
rationalize all denominators 1 solutions
Answer 423254 by lwsshak3(6522) on 2012-11-19 02:26:41 (Show Source):
You can put this solution on YOUR website!Use a sum or difference formula to find the exact value of the trigonometric function
cos 75degree
simplyfy the answer including any radicals
use integers or fractions for any number in the expression
rationalize all denominators
**
Identity: (s+t)=cos s cos t-sin s sin t
cos(75)=cos(45+30)=cos 45 cos 30-sin 45 sin 30
=√2/2*√3/2-√2/2*1/2
=√6/4-√2/4
=(√6-√2)/4
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Trigonometry-basics/682524: I don't understand how to solve the equation for (x) over the interval of [0,360(degrees)].
4cos(2x)= sqrt( 3 ) 1 solutions
Answer 423253 by lwsshak3(6522) on 2012-11-19 02:13:24 (Show Source):
You can put this solution on YOUR website!solve the equation for (x) over the interval of [0,360(degrees)].
4cos(2x)= sqrt( 3 )
cos(2x)=√3/4
2x=arccos√3/4
using calculator(cos^-1 key)
2x≈64.34º, 295.66º (in Q1 and Q4 where cos>0)
x≈32.17º, 147.83º
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Trigonometry-basics/682511: solve the equation in radians for all exact solutions.
2sqrt( 3 )cos(x/2)=-3 1 solutions
Answer 423252 by lwsshak3(6522) on 2012-11-19 01:54:46 (Show Source):
You can put this solution on YOUR website!solve the equation in radians for all exact solutions.
2sqrt( 3 )cos(x/2)=-3
**
2√3cos(x/2)=-3
cos(x/2)=-3/(2√3)
Identity: cos(x/2)=±√[(1+cos x)/2]
±√[(1+cos x)/2]=-3/(2√3)
square both sides
(1+cos x)/2=9/12
1+cos x=18/12=3/2
cos x=3/2-1=1/2
x=π/3+2πk, 5π/3+2πk, k=integer
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Trigonometry-basics/682514: solve the equation for x.
arctan x = arccos(5/13) 1 solutions
Answer 423251 by lwsshak3(6522) on 2012-11-19 01:26:22 (Show Source):
You can put this solution on YOUR website!solve the equation for x.
arctan x = arccos(5/13)
**
arccos(5/13) means an angle whose cos=5/13=adjacent side/hypotenuse
opposite side=√(13^2-5^2)=√(169-25)=√144=12 (by Pythagorean Theorem)
tan=opposite side/adjacent side=12/5
arctan x=the same angle whose cos=5/13
arctan(12/5) = arccos(5/13)
x=12/5
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