sec^2xcotx-cotx+tanx ? Verify id

You forgot an equals sign. I think what you mean is:

sec^2xcotx = cotx+tanx

As usual for these types of prioblems, start by replacing the sec, tan, and cot functions with their sin and cos equivalents, and then simplify. This one works right out - the only trick is to remember that cos^2x + sin^2x = 1.