Question

化简具体过程 谢谢

Answer 1

y=(sinx)^2+(cosx)^4
=[(sinx)^2+(cosx)^2]-2(sinxcosx)^2
=1-(2sinxcosx)^2/2
=1-(sin2x)^2/2

Answer 2

y=sin^4x+cos^2x=sin^2x(1-cos^2x)+cos^2x=sin^2x-sin^2xcos^2x+cos^2x=1-(1/4)(sin2x)^2