Thread: definite integral

1. definite integral

Evaluate the definite integral.

I really am not sure how to evaluate this integral.

Do i use the substitution method and set my u = 1+2x?

2. Try $x=\frac{u^2}2 -\frac1{\color{red}2}$.

edit: whoops. Thanks Linnus.

3. [quote=maddas;505552]Try [tex]x=\frac{u^2}2 -1

how did you get that x value?

4. Wouldn't it be
$
u= \sqrt{1+2x}
$

$
u^2=1+2x
$

$
u^2-1=2x
$

$
x= (u^2-1)/2
$

5. [QUOTE=rhcp1231;505555]
Originally Posted by maddas
Try [tex]x=\frac{u^2}2 -1

how did you get that x value?
I chose it so that the square root on the bottom would disappear, ie I wanted 1+2x = u^2. But like Linnus pointed out, I lost the 1/2. heh.