求cos(20°+x)cos(25°-x)-cos(70°-x)sin(155°+x)
sin(x+105°)cos(x-15°)-cos(x+105°)sin求化简
化简sin(x-25°)sin(65°-x)+cos(x-25°)cos(65°-x)的结果为
化简cos(180°+x)*sin(x+360°)/[sin(-x-180°)*cos(-180°-x)]
求值:sin(10°+x)cos(50°-x)+sin(50°-x)cos(10°+x)
【三角恒等变换】cos(33°-x)sin(63°-x)-cos(x+57°)sin(27°+x)
化简cos(15°-x)-根号3cos(15°+x)+cos(45°+x)
cos^2x+cos^2(x+120°)+cos^2(x+240°)
已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x
sin(sin(sin(sin(x)=cos(cos(cos(cos(x),X等于多少?
化简sin(x)(cos(x)+cos(3x)+cos(5x)+cos(7x))
cos x sin x=3,求cos x+sin x
证明:存在实数X,使得SIN x+cos X=60°