cos(25°+x)cos(20°-x)-cos(65°-x)sin(20°-x)
化简sin(x-25°)sin(65°-x)+cos(x-25°)cos(65°-x)的结果为
sin(x+105°)cos(x-15°)-cos(x+105°)sin求化简
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°)
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))
证明:存在实数X,使得SIN x+cos X=60°
化简cos²(-X)-【tan(360°+X)】/【sin(-X)】
sin(1/x)-cos(1/x)/x