Answer
$ \dfrac{1}{4.2} \sin (4.2 x-1) +C $
Work Step by Step
Our aim is to solve the integral $ \int \cos (4.2 x-1) \ dx$
Use formula:$ \int \cos (ax+b) \ dx =\dfrac{1}{a} \sin (ax+b)+C$
Let us consider that $a =4.2$ and $b=-1$
Now, $ \int \cos (4.2 x-1) \ dx =\dfrac{1}{4.2} \sin (4.2 x-1) +C $
or, $= \dfrac{1}{4.2} \sin (4.2 x-1) +C $
