How can I solve..
cotx + cosx sinx/ tanx +conx sinx/ cotx = csc2?

Please clarify. Without proper grouping symbols your problem statement is rather ambiguous.

Is this what you mean?:

Do you mean:



If so, then try rewriting using sin() and cos() in place of the tan() and cot() functons, and much of it collapses to a simpler looking equation. You'll end up having to determine the arc tan of a number.