Show algebraically how to confirm that cos2x=cos^2x-sin^2x using the sum and difference identities

2 answers

huh?
cos 2 x = cos ( x+x )
= cos x cos x - sin x sin x
= cos^2 x - sin^2 x
no
Similar Questions
  1. Use the identities cos^2 x + sin^2 x =1and cos2x=cos^2 x -sin^2 x to show that cos^4 x -sin^4 x = cos2x Im not sure how, I can
    1. answers icon 1 answer
    1. answers icon 5 answers
  2. If sinx = 1/4 Find the exact value of cos2xI used the formula for double angle identities : cos2x = 1-2sin^2x and got the answer
    1. answers icon 1 answer
  3. Which of the following are identities? Check all that apply.(Points : 2) sin2x = 1 - cos2x sin2x - cos2x = 1 tan2x = 1 + sec2x
    1. answers icon 1 answer
more similar questions