设f(sin x)=cos2x+1,求f(cos x)._数学解答

设f(sin x)=cos2x+1,求f(cos x).

人气：448 ℃　时间：2020-03-27 18:27:00

解答

f(sinx)=cos2x+1
=1-2sin^2 x+1
=2-2sin^2 x
f(cosx)=2-2cos^2 x
=2(1-cos^2 x)
=2sin^2 x