69 Answered Questions for the topic Trigonometry Identities

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)

Sin(45-x)=cos(45+x) prove the identity

Sin(45-x)=cos(45+x) How to prove this identity? 

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... more

Write the expression as the sine or cosine of an angle.

cos7y cos3y -sin 7y sin3y= ?

Solve for x in the equation 4cos4x=0

i need step by step soln plz thank u

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

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

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

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

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... more

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!!

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


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... more


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!

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... more

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. 

Trig identities!

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

prove the identity


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)?... more

Solve for all values of 2sinx-1=0. in terms of pi

(show work)  where 0≤x<2π  

How to prove this identity

tan3x - tan2x- tanx = tan3xtan2xtanx

verify identity


Rewrite 6(sin5x)cos2x

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

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

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

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.

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... more

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