You can
put this solution on YOUR website! Sorry, that is not an identity.
Put calculator in radian mode, let x=1 radian. Calculate:
Put it in your TI exactly this way:
cos(3p/4+1)cos(2p+1)(1/tan(3p/2-1)+1/tan(2p+1))
and you get -1.161134824, not 1.
There has to be a typo.
Edwin