C= [tex]sin^6(\pi+x)+cos^6(\pi-x)-2sin^4(x+2\pi)-sin^4(x-\frac{3\pi}{2})+cos^2(x-\frac{\pi}{2})[/tex]
Hazz giờ mới rảnh em
giúp tận cùng đây
[tex]C = sin^{6}x + cos^{6}x - 2sin^{4}x - cos^{4}x + sin^{2}x[/tex]
= [tex](sin^{6}x - sin^{4}x) + (cos^{6}x - cos^{4}x) - sin^{4}x + sin^{2}x[/tex]
= [tex]sin^{4}x(sin^{2}x - 1) + cos^{4}x(cos^{2}x - 1) + sin^{2}x(1 - sin^{2}x)[/tex]
= [tex]-sin^{4}xcos^{2}x - cos^{4}xsin^{2}x + sin^{2}xcos^{2}x[/tex]
= [tex]-sin^{2}xcos^{2}x(sin^{2}x + cos^{2}x) + sin^{2}xcos^{2}x = 0[/tex]