# evaluating integral

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• May 14th 2010, 12:02 AM
dorkymichelle
evaluating integral
Evaluate the integral by interpreting it in terms of areas.
37. $\int^0_{-3} (1+\sqrt{9-x^2})*dx$
the answer is $3+\frac{9}{4}*\pi$
Where .. the heck did $\pi$ come from?
I was trying to do
$\frac{b-a}{n}$
$= \frac{0-3}{n}$
$=\frac{-3}{n}$

and then $x_{i}$ as $\frac{-3i}{n}-3$
then plugging $x_{i}$ into $f(x)*dx$ then solving for the limit. It came out to be a super complicated root problem so I look in the back to see if I'm in the right track.. and theres a $\pi$ in the answer...
I think I'm missing something here... how is this integral end up having a $\pi$?
• May 14th 2010, 12:05 AM
matheagle
delete this
double post?
• May 14th 2010, 12:15 AM
dorkymichelle
oops, must've clicked submit two times, how do i delete this? or do i need a moderator?
• May 14th 2010, 12:20 AM
matheagle
hit edit and look for where it says delete