`int (4x-2/(2x+3)^2) dx` Find the indefinite integral

Expert Answers

An illustration of the letter 'A' in a speech bubbles

`int (4x - 2/(2x+3)^2)dx`

To solve, express it as difference of two integrals.

`= int 4x dx - int 2/(2x+3)^2dx`

Then, apply negative exponent rule `a^(-m)=1/a^m` .

`= int 4xdx - int 2(2x+3)^(-2)dx`

For the second integral, apply the u-substitution method. 

`u = 2x + 3`

`du = 2dx`

Expressing the second integral in terms of u variable, it becomes:

`=int 4xdx - int (2x+3)^(-2) * 2dx`

`=int 4xdx - int u^(-2) du`

For both integrals, apply the formula `int x^ndx= x^(n+1)/(n+1)+C` .

`= (4x^2)/2 - u^(-1)/(-1) + C`

`=2x^2 + u^(-1) + C`

`= 2x^2 + 1/u + C`

And, substitute back `u = 2x + 3`

`=2x^2+1/(2x+3)+C`

 

Therefore, `int (4x - 2/(2x+3)^2)dx=2x^2+1/(2x+3)+C` .

See eNotes Ad-Free

Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Get 48 Hours Free Access
Approved by eNotes Editorial Team