若sin(30-x)=1/3,则cos(120+2x)等于?
若sin(30-x)=1/3,则cos(120+2x)等于?
SIN(30度-X)=1\3,则COS(120度+2X)等于多少.
若sin x/2-cos x/2=1/3,则sin x=
若sin x/2 - cos x/2 = 1/3,则sin x=?
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+
sin(sin(sin(sin(x)=cos(cos(cos(cos(x),X等于多少?
若sin(兀/3一x)=1/4,则cos(兀/3+2x)等于
证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4
设(2cosx-sinx)(sin^2x+2cos^2x)=0,则(2cos^2x+sin^2x)/(1+tanx)等于
若sin((pi/6)+x)=1/3,则cos((pi/3-x)=?cos((2pi/3)+x)=?
已知sin(x-3π/4)cos(x-π/4)=-1/4,则cosx等于
y=sin^2x-3sinxcosx+4cos^2x是否等于y=sin^2x+cos^2x+3cos^2x-3/2*si