sin(a-π/4)能化简成什么
求证:2sin(π/4+a)sin(π/4-a)=cos2a
证明:2sin(π/4+a)sin(π/4-a)=cos2a
已知a属于(0,π/2),且2sin^2 a-sin a cos a-3cos^2 a=0,求SIN(a+兀/4)/SI
化简:sin(-a)cos(2π+a)sin(-a-π)
sin(a-π/4)+cos(a+π/4)怎么解?
sin(π/4-a) cos(a-π/4)化简
sin a/2=4/5,且a属于(π/2,π),求sin a,cos a的值
已知sin(π/4+2a)sin(π/4-2a)=1/4,a∈(π/4,π/2)求2sin方a+tana-cota-1
已知方程sin(a-3π)=2cos(a-4π),求 [sin(π-a)+5cos(2π-a)]/[2sin(3π/2-
已知sin(a-3π)=2cos(a-4π),求(sin(π-a)+5cos((3π/2)-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
(1-sin^6a-cos^6a)/(sin^2a-sin^4a)