# Math Help - Demand function and finding elasticity

1. ## Demand function and finding elasticity

I wasn't sure whether this should go in the Calculus or Business sections(it's a calculus class but a business themed problem) my apologies if it is in the wrong section.

For the demand function q = 800 - 2p^2 find the elasticity when p = $12 and q is the number of items produced. 2. Originally Posted by Mathamateur I wasn't sure whether this should go in the Calculus or Business sections(it's a calculus class but a business themed problem) my apologies if it is in the wrong section. For the demand function q = 800 - 2p^2 find the elasticity when p =$12 and q is the number of items produced.
Now the definition of elacticity that I have here is:

$E=(\%\mbox{ age change in demand})/(\%\mbox{ age change in price)}=\frac{dq}{dp}\ \frac{p}{q}$.

Now:

$\frac{dq}{dp}=-4p$,

so:

$
E=-4p\ \frac{p}{800-2p^2}
$

So if $p=12$, the:

$
E=-4 \times 12\ \frac{12}{800-288}=-1.125
$

RonL