已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值
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![已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值](/uploads/image/z/1063599-15-9.jpg?t=%E5%B7%B2%E7%9F%A5sina%3D3%2F5%2Ca%E2%88%88%28%E5%85%80%2F2%2C%E5%85%80%29%2C%E6%B1%82tana%E5%92%8Csin%28-%CF%80-a%29%2Fsin%289%CF%80%2F2%2Ba%29%E7%9A%84%E5%80%BC%E5%B7%B2%E7%9F%A5sina%3D3%2F5%2Ca%E2%88%88%28%E5%85%80%2F2%2C%E5%85%80%29%2C%E6%B1%82tana%E5%92%8Csin%EF%BC%88-%CF%80-a%EF%BC%89%2Fsin%EF%BC%889%CF%80%2F2%2Ba%29%E7%9A%84%E5%80%BC)
已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值
已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值
已知sina=3/5,a∈(兀/2,兀),
求tana
和sin(-π-a)/sin(9π/2+a)的值
已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值已知sina=3/5,a∈(兀/2,兀),求tana和sin(-π-a)/sin(9π/2+a)的值
(1)sina=3/5,a∈(兀/2,兀),
所以cosa=-4/5
tana=sina/cosa=-3/4
(2)sin(-π-a)/sin(9π/2+a)
=sina/cosa=-3/4