# Price Elasticity of Demand Help

1. Jun 18, 2011

### jweber

q= (39/3.6)^2/3

p=(39/(3.6^3/2)

Find price elasticity of demand when p=\$3.6. I already substituted the 3.6 in there.

I keep getting 1.5 but its saying it wrong please solve and help.

2. Jun 18, 2011

### Pyrrhus

Could you post the complete problem statement?

you know that elasticity is defined as a logarithmic derivative

$\epsilon = \frac{\partial \ln y}{\partial \ln x}$

Last edited: Jun 18, 2011
3. Jun 19, 2011

### HallsofIvy

Staff Emeritus
By "already substituting the 3.6 in there", you have made it impossible to answer. We need to know the demand as a function of the proce.