sin(π/6+a)=3/5,π/3
求证 cos(A)+ 根号3sin(A)=2sin(π/6+A)
已知sin(π/6+a)=1/3,求sin(5/6π-a)+cos2(7/6π+a)
若sin(π/6-a)=根号3/3,则sin(7π/6-a)=
已知sin(π/6+a)=(根号3)/3,求sin(2π/3+a)?
已知sin(a+π/6)+cosa=4/5倍根号3,则sin(a+π/3)=
已知cos(π/2+a)=2sin(a-π/2)求sin(π-a)+cos(a+π)/5cos(5π/2-a)+3sin
化简:cos(π/3+a)+sin(π/6)+a=
sin(π+a)=3/5,cos(-a)
设f(a)=sin^2a+cosacos(π/3+a)-sin^2(π/6-a)π
已知sin(a-3π)=2cos(a-4π),求(sin(π-a)+5cos((3π/2)-a))/(2sin(3π/2
已知方程sin(a-3π)=2cos(a-4π),求 [sin(π-a)+5cos(2π-a)]/[2sin(3π/2-
已知sin[a-b]cos a-cos[b-a]sin a=3/5,b是第三象限角,求sin[b+5π/4]的值