69 Answered Questions for the topic Trigonometry Identities

11/30/16

#### Need Urgent Trig Help!!

Find the value for sin (θ) if the following conditions hold: cos(2(theta)) = 3/5 and 90(degrees) < (theta) < 180(degrees)
A. (1/25) B. (sqrt5/25) C. (2 sqrt5/5) D. (sqrt5/5)

06/12/16

#### Can someone walk me through simplifying sec(?)?^2 * cot(?) * cos(?) =

I thought it'd be (1 / cos(θ)2) * (1 / tan(θ)) * (cos(θ) / 1)
Which would get you cos(θ) / cos(θ)2 * tan(θ)
And then coming out to 1 / cos(θ) * tan(θ)
but that doesn't make sense...
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03/23/16

#### If cos(pi/2-X) =4/5. Find sin(-x)

Please help me solve this equation to better help me to understand trig Identites.

03/15/16

#### Find the exact value if sin x= -5/13, cos y= 4/5, 3pi/2<x<2pi, and 3pi/2<y<2pi what is tan(x+y)

I am a little confused on this and it would be nice if someone could work through it so I can understand this problem

11/29/15

#### Please help me with these identity proofs!!

1) (cscx + cotx) / (tanx + sinx) = cotxcscx
2) (1/secx) -secx = -sinx
3) (1-tan^2x / 1-cot^2x) = -tan^2x

11/24/15

#### cos(11pi/12) using Sum and difference identities

could someone explain finding cos(11pi/12) using Sum and difference Identities.
it must use one of...
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10/25/15

#### sin^2 x/2 = tanx-sinx/2tanx

=(sinx/cosx - sinx)/ (2sinx/cosx) = sinx-sinxcosx/cosx • cosx/2sinx = sinx (1-cosx)/2sinx = 1-cosx/2 now im lost help!!

10/24/15

#### Express cos4x as a trig function of x

Using only the double angle identities how to solve for this? im stucked after 2cos^2 (2x) -1

10/22/15

#### 1/8sin29.5cos29.5

I know that i should multiply something to it for it to become 2sinAcosA for me to be able to solve it. Unfortunately, if i multiply2/2 to it will just become 2/16 that will just bounce back to 1/8...
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10/19/15

#### Tan(theta+30)

tana+tanb/1-tanatanb
im confused becase sqrt of 3 over 3 is the value of tan 30 so its hard to solve the arithmetic and the algebra. help please!

10/07/15

#### Verify/prove: (1-cos^2x)(1+cos^2x) = 2sin^2x-sin^4x

I chose to manipulate the left hand side. So i got 1+cos2x-cos2x-cos4x
when i simplify it will be 1-cos4x i will break it into pieces so (1-cos2x)(1+cos2x) i can change the first term to sin so...
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10/03/15

#### Find the solutions of the equation that are in the interval [0, 2p). (Enter your answers as a comma-separated list.

If there is no solution, enter NO SOLUTION.) 2 -2 sin t = 2 sqrt(3)cos t
My solutions were pi/2, 7pi/6, and 11pi/6.

04/27/15

#### Trig identities!

Please help, I have no idea!
Solve the following trigonometric equation sin^2x - cos^2x = 1/4.

01/08/15

#### How can I solve sin(2x) = sin(x/2) for all values of x?

I can find x = 0, and also can show that cos x = (1/4)*(-1+/-sqrt(5)), but I don't know how I should have known that the latter cosines of x correspond to angles involving fifths of pi (radians)?...
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12/31/13

#### Use the sum or difference formulas to determine: A. sin105 degrees B. tan15 degrees

This is for my trig class. Thanks for the help!

12/12/13

#### Verify the identity 1/tan(theta)csc(theta) = cos(theta)

This is for my trig class, and the directions say to verify the identity. Thanks so much.

12/11/13

#### Q2 POW #3 -Trig Identities

1) given the double angle identity for cosine: cos2θ=cos2θ-sin2θ
Prove: cos3θ = cos3θ - 3cosθsin2θ
and: cos4θ = cos4θ - 6cos2θsin2θ + sin2θ
2) Continue this process, finding an...
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