@Carl Love Thank you VERY MUCH. I new i was doing something wrong.

I apreciate this. Have a nice day.

P.D'A

@Kitonum Hello, thank you for you rreply. I typed COS^25x-SIN^25x=COS10X to check if my calculations in my homework for school where correct, but it says that there are no steps to visualize this excercise. I proceeded to input another excercise like this TAN3x=3TANx-tan^3x/1-3TAN^2x to check my results but it says the same. I really think I am doing something wrong. And also it says that there is a part missing in the problem while i am typing, but it is an equation i need to prove the identity.

Thank you very much for your help.

Have a nice day.

Perla

P.S.= it accured to me that i wrote inverse funtion in the main title. My apologies, I was talking with a friend while I wrote the post and accidentaly put down the title wrong. Accept my apologies.