Enter your expression, then press the ^ key, then your exponent. If you exponent is an expression encase it in perentheses ()Ex. 3x5x+2 Press 3 x ^ (5x+2)
The TI-83 does not have the cot button, however, if you type 1/tan( then this will work the same as the cot since cot=1/tan. The other way to do this is to type (cos(x))/(sin(x)) where x is the angle...
With most of the TI calculators, you have to press the "2nd" button (usually in the top left corner, by the screen) and then the "ON/CLEAR" button (usually in the top right corner, by the screen).