已知sin(π/4—a)=5/13,0<a<π/4,则cos2a等于多少?
已知sin(π/4—a)=5/13,0<a<π/4,则cos2a等于多少?
若cos2a/sin(a-π/4)=-√2/2,则cosa+sina等于多少?
已知sin(π/4-a)=5/13(0<a<π/4),求cos(π/4+a)/cos2a
已知sin(π /4+a)=12/13,a∈(0,派/4),求cos(a-派/4)/cos2a,
已知sina=1/2+cosa,且a∈(0,π/2),则cos2a/sin(a-π/4)的值为多少?
已知tana+cota=5/2,求cos2a和sin(2a+π/4)
已知sin(π/4-a)=5/13,a∈(0,π/4),求cos2a/cos(π/4+a)的值
已知sin(π/4-a)=5/13 a∈(0,π/4)求cos2a/cos(π/4+a)
0<a<π/4.sin(π/4-a)=5/13.求cos2a/cos(π/4+a)
已知Sin(a+π/4)/cos2a=二分之根6求sin2a
已知根号2倍的sin(a+ pei/4)=3sina,则(2sin平方a+cos平方a)/cos2a等于()
若cos2a/sin(a-π/4)=-根号2/2 则sina+cosa 的值为多少?