化简sin(π/4+a)cosa-sin(π/4-a)sina=
Sin^4a+Sina*Cosa+Cos^2a化简
若cos(a+B)*cosa+sin(a+B)*sina=-4/5,则sin(π/2-B)
已知sin(a/2)=4/5,a∈(π,2π),求sina,cosa,tana.
已知sin(a/2)=4/5,a∈(π,2π),求sina,cosa,tana
若sinA+cosA/sinA-cosA=2,则sin(A-5π)*sin(3π/2-A)等于?
sin(π+a)=sinπcosa+cosπsina=-sina中sinπcosa+cosπsina=-sina是怎么得
化简:sin(a-B)cosa-1/2[sin(2a+B)-sinB]=?已知cos(a-π/6)+sina=4√3/5
若sin(a-π/4)/cos2a=-根号2,则sina+cosa=
sinA+cosA=1/2,则sin(A+π/4)=?
若sina+cosa=1/2,则sin(a+π/4)=?
化简sina^8-cosa^8-sin^6a+cos^6a+sin^4a
若 cos2a/sin(a-π/4)= -√2/2,求cosa+sina的值.