how do I solve arccos(3/5)+arccot(1/7) ? am i supposed to do cos(arccos(3/5)+arccot(1/7)) making it (3/5)+cos(arccot(1/7)) ? but if so how do i continue?
when you say "solve" what do you mean. because there is no nice way to "simplify" this without a calculator, which is what you seem to be asking us to do. (what you did was totally wrong by the way. cosine is not a linear operator, so you can't apply it as you did. $\displaystyle \cos (A + B) = \cos A \cos B - \sin A \sin B$, secondly, if you are to simplify, you cannot do it by applying a trig function, you'd be changing the value!)