sin^2 x+sinx=1,则cos^2 x+cos^4 x=_____

问题描述:

sin^2 x+sinx=1,则cos^2 x+cos^4 x=_____

sin^2 x+sinx=1,
sinx=1-sin^2 x=cos^2 x
cos^2 x+cos^4 x=sinx+(sinx)^2=1