Rita is proving that the following trigonometric identity is true:
cos(−θ)/sin(−θ)=−1/tanθ
Which step would be the first line of her proof?
A) cosθ /sin θ= −1/tan θ
B) cosθ /−sin θ= −1/ tanθ
C) cos(−θ) ⋅ tanθ = sin(−θ)
D) cos(−θ) / sinθ = −1/tanθ