化简sin(x-25°)sin(65°-x)+cos(x-25°)cos(65°-x)的结果为

化简sin(x-25°)sin(65°-x)+cos(x-25°)cos(65°-x)的结果为 cos(27°+x)sin(57°+x)-sin(207°+x)sin(327°+x) sin(30°+x)-sin(30°-x)等于多少? 化简sin(x+120°）+sin（x+240°） 化简:sin^A*sin^A+sin(A-60°)*sin(A-60°)+sin(A+60°)* cos(25°+x)cos(20°-x)-cos(65°-x)sin(20°-x) 化简sin(-2x) 化简sin²x 化简cos(180°+x)*sin(x+360°)/[sin(-x-180°)*cos(-180°-x)] 化简sin^(a-30°)+sin^(a+30°)-sin^a化简sin^2(a-30°)+sin^2(a+30°)-sin^2a 化简：sin(x+60°)+2sin(x-60°)-根号下3cos(120°-x) 化简：sin（x+60°）+2sin（x-60°）-√3cos（120°-x）= 化简sin(60°+α)-sin(60°-α)急用. sin(30°+β)-sin(30°-β)化简 sin(33°-x)cos(27°+x)+cos(33°-x)sin(27°+x) 化简sin（171°）sin（99°）+sin（-171°）sin（-261°） sin²1°+sin²2°+sin²3°+...+sin²89°化简 sin(2x+90°)等于什么