sin^8X+cos^8X+4sin^2Xcos^2x-2sin^4xcos^4X(化简)
问题描述:
sin^8X+cos^8X+4sin^2Xcos^2x-2sin^4xcos^4X(化简)
答
原式=sin^8X-2sin^4xcos^4X+cos^8X+4sin^2Xcos^2x=(sin^4x-cos^4x)^2+4sin^2Xcos^2x=[(sin^2x-cos^2x)(sin^2x+cos^2x)]^2+4sin^2Xcos^2x=(sin^2x-cos^2x)^2+4sin^2Xcos^2x=sin^4x-2sin^2Xcos^2x+cos^4x+4sin...