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