Question

1-tanx/1-cotx

Answer 1

Is this the problem?
\[ \frac{1-tan(x)}{1-cot(x)}\]

Answer 2

If so, since tan(x) = 1/cot(x), let tan(x)=u and cot(x)=1/u. The result easily simplifies with this substitution. When you're done, replace u with tan(x) and you're done.
Good luck.

Answer 3

\[\frac{ 1-tanx }{ 1-\frac{ 1 }{ tANX } }\]=\[\frac{ tanx(1-tanx) }{tanx-1 }=-tanx\]