What is the price elasticity?? p=50, q=50e^(-0.02)?

The price elasticity of demand is defined as:

\(\displaystyle \displaystyle E_d\equiv\frac{p}{q}\cdot\frac{dq}{dp}\)

You are given \(\displaystyle p=50\).

Now, your quantity demanded \(\displaystyle q\) should be a function of price \(\displaystyle p\), but seems to be a constant instead. Are you certain you have given the correct expression for quantity demanded?
 
The price elasticity of demand is defined as:

\(\displaystyle \displaystyle E_d\equiv\frac{p}{q}\cdot\frac{dq}{dp}\)

You are given \(\displaystyle p=50\).

Now, your quantity demanded \(\displaystyle q\) should be a function of price \(\displaystyle p\), but seems to be a constant instead. Are you certain you have given the correct expression for quantity demanded?

My bad, you are right!

q = 50e^(-0.02p)
 
Okay, so you need to find:

\(\displaystyle q(50)\) and \(\displaystyle \displaystyle \frac{dq}{dp}|_{p=50}\).

Do you know how to find these values?
 
I'm not too sure, I have had 5 attempts but they have all been wrong, I was really hoping somebody could explain to me step by step how to solve this problem. :)
 
I'm not too sure, I have had 5 attempts but they have all been wrong, I was really hoping somebody could explain to me step by step how to solve this problem. :)

Please show us in detail - at least one of your wrong attempts.
 
Okay, so for one of my attempts, I differentiated the p/q equation:

[(50e^(-0.02p)(1)-(p)(50e^(-0.02p))(-0.02)]/(50e^(-0.02p))^2

with that, I got 1.
To find \(\displaystyle \dfrac{dq}{dp}\) you differentiate \(\displaystyle q = e^{(-0.02p)} = e^u \implies \dfrac{dq}{du} = e^u\ and\ \dfrac{du}{dp} = -0.02.\)

\(\displaystyle So \dfrac{dq}{dp} = \dfrac{du}{dp} * \dfrac{dq}{du} = -0.02e^{(-0.02p)}\)

So what does \(\displaystyle \dfrac{p}{q}\) equal? So what does \(\displaystyle \left|\dfrac{p}{q} * \dfrac{dq}{dp}\right|\) equal?

You now have a general expression in p. So if p = 50, then what?
 
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