Question

could some one tell me if this way of solving is correct?

Answer 1

Which way

Answer 2

No

Answer 3

why? what would be the correct way to do it?

Answer 4

$$\bf \cfrac{tan(u-1)}{tan(u+1)} = \cfrac{cot(u)}{1+cot(u)} \ \ \ ?$$

Answer 5

$$\bf \cfrac{tan(u-1)}{tan(u+1)} = \cfrac{1-cot(u)}{1+cot(u)}\ \ \ ?$$ rather

Answer 6

that the question i have to establish the identities an show the steps of how to do it