Question

How do you prove `cosA/(1-tanA) = (sinA)/(1-cotA)`?

Answer 1

This relationship can not be proven because, in general, it is not true

For example if `A= pi/6`
`color(white)("XXXX")` `(cos A)/(1-tan A) = 2.05`

`color(white)("XXXX")` `(sin A)/(1-cot A) = -0.68`

(Perhaps some of the terms in your relation should have squares(?))