cos(30°-2x)=-1,x等于?
sin(sin(sin(sin(x)=cos(cos(cos(cos(x),X等于多少?
2(cos x)^2=1+cos 2x,
sin x(sin x+cos x)=1求x等于多少
SIN(30度-X)=1\3,则COS(120度+2X)等于多少.
若sin(30-x)=1/3,则cos(120+2x)等于?
设(2cosx-sinx)(sin^2x+2cos^2x)=0,则(2cos^2x+sin^2x)/(1+tanx)等于
(1+cos x/2)/2等于多少?
(tanx+1/tanx)cos^2 x等于
设x为锐角,若cos(x+30°)=4/5 ,sin(2x+15°)等于?
设f(x)=cosx/cos(30°-x),则f(1°)+f(2°)+……+f(60°)的值等于?
sin(-x) cos(-x)等于多少
已知sin X+cos X=m,|m|小于等于根号2且|m|不等于1,求sin X^3+cos X^3,sin X^4+