I picked a random angle (20ยบ) and tested your "identity".
the left side was equal to 1
when you typed
cotxcot2x ...
did you mean
cotxcot(2x)... or cotxcot2x ... ?
prove that
cotxcot2x-cot2xcot3x-cot3xcotx=1
1 answer
cotxcot2x-cot2xcot3x-cot3xcotx=1
1 answer