Question

Evalute this integral

Answer 1

(1/2)sin(2x) + C

Explanation:

`y=2x\\(dy)/(dx) =2\\\ dx=(dy)/(2) \\\int\limits {cos 2x} \, dx \\\int\limits {cos(y) } \, (dy)/(2) =(1)/(2) \\\int\limits {cos(y) } \, dy=(1)/(2)sin(y) \\ substitute / y=2x\\\int\limits {cos 2x} \, dx = (1)/(2)sin(2x) +C`