sinθ=12/13,θ属于(0,90°)
cosθ>0,tanθ>0
cosθ=5/13
tanθ=sinθ/cosθ=(12/13)/(5/13)=12/5
sin(θ+60°)
=sinθcos60°+cosθsin60°
=12/13*1/2+5/13*√3/2
=(12+5√3)/65
已知sin∝=12/13,∝∈(0,丌),求cos∝,tan∝.
sinθ=12/13,θ属于(0,90°)
cosθ>0,tanθ>0
cosθ=5/13
tanθ=sinθ/cosθ=(12/13)/(5/13)=12/5
sin(θ+60°)
=sinθcos60°+cosθsin60°
=12/13*1/2+5/13*√3/2
=(12+5√3)/65