數學三角函數

sinθ-cosθ＝1/3 兩邊平方

(sinθ)^2-2*sinθ*cosθ+(cosθ)^2=1/9

1-2*sinθ*cosθ=1/9

-2*sinθ*cosθ=-8/9

sinθ*cosθ=4/9


題目可能應該是

secθ-cscθ

=(1/cosθ)-(1/sinθ)

=(sinθ-cosθ)/(sinθ*cosθ)

=(1/3)/(4/9)

=(1/3)*(9/4)

=3/4

sinθ - cosθ = 1/3

sin 58.633 - cos 58.633 = 1/3

So θ = 58.633°

sec 58.633 - cos 58.633 = 0.65065 not 3/4

Your answer is wrong.