Simplify the expression :
(2 + 3p) (2) =
please help

Using the foil method, multiply 2 to 2 and 3p. It would become (4+6p) and that is your answer

So the question ask to find how to integrate cos2t without using substitution and base on my research, the integral of the cos2t  = (1/2) sin(2t), and negate the said integral because the derivative of cosx is - sinx. I hope you are satisfied with my answer and feel free to ask for more