I think you're allowed to use them without derivation. (Also, by derivation do you mean by the limit definition or by finding say dy/dx of sinx and taking the reciprocal?)
I think you're allowed to use them without derivation. (Also, by derivation do you mean by the limit definition or by finding say dy/dx of sinx and taking the reciprocal?)
I was always under the belief that it was not required, especially as it is given to you on the formula sheet. I thought (with regards to its use and no other questions that explicitly requires a derivation), that it could be used just as the derivate of sinx is cosx.