What is the integral of int sin(2x)dx?

1 Answer
Mar 17, 2016

-1/2cos(2x)+C

Explanation:

We will use the rule:

intsin(u)du=-cos(u)+C

So, if we have

intsin(2x)dx

we should set

u=2x" "=>" "du=2dx

In order to have a 2dx in the integral expression, multiply by a 2 on the inside and balance it with a 1/2 on the outside:

=1/2intsin(2x)*2dx

Substitute:

=1/2intsin(u)du

Using the initial rule, this becomes:

=-1/2cos(u)+C

Since u=2x,

=-1/2cos(2x)+C