化简:sin^4 x-sin^2 x+cos^2 x
问题描述：
化简:sin^4 x-sin^2 x+cos^2 x
答
sin^4 x-sin^2 x+cos^2 x=sin^2x(sin^2x-1)+cos^2x=-sin^2xcos^2x+cos^2x=cos^2x(-sin^2x+1)=cos^4x
化简:sin^4 x-sin^2 x+cos^2 x
sin^4 x-sin^2 x+cos^2 x=sin^2x(sin^2x-1)+cos^2x=-sin^2xcos^2x+cos^2x=cos^2x(-sin^2x+1)=cos^4x