化简[cos(4a-π/2)*sin(π/2-a)*cos2a]/[(1+cos2a)(1+cos4a)*cosa
化简[cos(4a-π/2)*sin(π/2-a)*cos2a]/[(1+cos2a)(1+cos4a)*cosa
三角比:[cos(4a-PAI/2)*sin(PAI/2-2a)]/[(1+cos2a)*(1+cos4a)]
化简:sin2a/sin(π+a)+cos2a+1/cosa
化简[2sin2a/(1+cos2a)]*(cos^2a/cos2a)
已知sin a+cos a=1/3,a属于(π/2,π),求cos2a
三角函数证明题(1)3+cos4a-4cos2a=8sin~4次方 a(2)tanatanb/tan2a-tana +
cos2A+cos(4π/3-2A)化简,
cos2a/sin(a-π/4) =-根号(2)/2,则cosa+sina的值为?
若 cos2a/sin(a-π/4)= -√2/2,求cosa+sina的值.
若cos2a/sin(a-π/4)=-√2/2,则cosa+sina等于多少?
若cos2a/sin((a-(π/4))=-(√2)/2,则cosa+sina的值为
若sin(a-π/4)/cos2a=-根号2,则sina+cosa=