Trouble completing the square on the integral

[en bloc]

Homework Statement

http://c811106.r6.cf2.rackcdn.com/se05h01043.png

Homework Equations

The Attempt at a Solution

The negative sign in front of x^2 is giving me trouble.

When i complete the square i get; $\sqrt{}-x^2-4x+4 -4$

There's some algebra that i don't understand.

 

[SammyS]

Homework Statement

http://c811106.r6.cf2.rackcdn.com/se05h01043.png

Homework Equations

The Attempt at a Solution

The negative sign in front of x^2 is giving me trouble.

When i complete the square i get; $\sqrt{-x^2-4x+4 -4}$

There's some algebra that i don't understand.

First, complete the square for $x^2+4x\,.$ Then take the negative of the result.

 

[HallsofIvy]

$-x^2- 4x= -(x^2+ 4x)$

Now complete the square for $x^2+ 4x$.