SOLUTION: find the exact value using a double angle identity cos(3pi/2)

Question 767421: find the exact value using a double angle identity
cos(3pi/2)
Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
find the exact value using a double angle identity
cos(3pi/2)
***
cos(3π/2)=cos(2*3π/4)
cos2x=cos^2x-sin^2x
cos(2*3π/4)=cos^2(3π/4)-sin^2(3π/4)=(-√2/2)^2-(√2/2)^2=1/2-1/2=0
calculator check:
cos(3π/2)=0
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