Answer
$ -\sin (-x+1) +C $
Work Step by Step
Our aim is to solve the integral $ \int \cos (-x+1) \ dx$
Use formula:$ \int \cos (ax+b) \ dx =\dfrac{1}{a} \sin (ax+b)+C$
Let us consider that $a =-1$ and $b=1$
Now, $ \int \cos (-x+1) \ dx =\dfrac{1}{-1} \sin (-x+1) +C $
or, $= -\sin (-x+1) +C $
