# [SOLVED] Can't figure out integral with sqrt

• May 4th 2010, 08:15 AM
x3bnm
[SOLVED] Can't figure out integral with sqrt
I can't seem to figure out the following integration:

$
\int_0^1 2\sqrt{1+t^2} dt = \left[2\left(\frac{t}{2}\sqrt{1+t^2} + \frac{1}{2}\ln\left(t+\sqrt{1+t^2}\right)\right)\r ight]_0^1
$

How do i reach the right side of equal sign?
Can anyone kindly tell what method is used for
the above integration?
• May 4th 2010, 08:22 AM
shawsend
I think it's trig substitution. Let $t=\tan(\theta)$
• May 4th 2010, 08:27 AM
x3bnm
You are absolutely right. How did i miss that? Thanks a lot for help.