SOLUTION: Verify identity. 2sin^2(x)-1=sin^4(x)-cos^4(x)

Algebra ->  Trigonometry-basics -> SOLUTION: Verify identity. 2sin^2(x)-1=sin^4(x)-cos^4(x)      Log On


   

Question 927954: Verify identity.
2sin^2(x)-1=sin^4(x)-cos^4(x)
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
2sin%5E2%28x%29-1=sin%5E4%28x%29-cos%5E4%28x%29

start with right side
sin%5E4%28x%29-cos%5E4%28x%29
=%28sin%5E2%28x%29-cos%5E2%28x%29%29%28sin%5E2%28x%29%2Bcos%5E2%28x%29%29

=%28sin%5E2%28x%29-%281-sin%5E2%28x%29%29%29%28sin%5E2%28x%29%2B%281-sin%5E2%28x%29%29%29

=

=%282sin%5E2%28x%29-1%29%281%29

=2sin%5E2%28x%29-1 which is our left side