Question

Please could I get some help with this last question I have been waiting for 2 hours please!

I just need it in (P/X)/DP/DX form please!

Demand function
128
------ +2
x^2

Quality demand x = 4

Find the price elasticity of demand for the demand function at the indicated x-value.

Answer 1

@JackleBee

Answer 2

you mean you want to get rid of the fraction?

Answer 3

yes

Answer 4

shoot, did you try logs?

Answer 5

nope, not sure what that is.

Answer 6

y doesn't equal to anything at the moment right?

Answer 7

right

Answer 8

Ive tried different methods, but not getting a clear answer

Answer 9

which methods did you try? you might have missed a step

Answer 10

I tried 2x= 128+ 2 to get rid of the fraction, but I got the wrong answer

Answer 11

lol why 2x?

Answer 12

I just tried to move the x^2 over to one side then solve 128/2 to get 64

Answer 13

128
------ +2 = y
x^2

did you try square root?

Answer 14

like move it, and then square root?

Answer 15

man, i'm stumped on this one, I'll get this other guy who might help. ;p @satellite73

Answer 16

sorry dude, but I want to see how this is solved as well xD

Answer 17

same here. I know the process, but the fraction is throwing me off

Answer 18

@satellite73 you think you can help us sir?


and yeah, that fraction xD

Answer 19

I think I remember @satellite73

Answer 20

I'm trying to get this problem into (P/X)/DP/DX form, but the fraction is throwing me off

Answer 21

What is P when x = 4 ?

Answer 22

10?

Answer 23

err 10

Answer 24

so you'll have P/x = 10/4 = 2.5

Answer 25

dP/dx is simply the derivative of P with respect to x

Answer 26

think of it as P = 128x^(-2) + 2 and use the power rule

Answer 27

\[\frac{ -256 }{ x^3 }\]

Answer 28

good

Answer 29

now I think you plug in x = 4 into dP/dx

Answer 30

I get -4

Answer 31

I got 2.5/-4 = -5/8

Answer 32

so, (P/x)/(dP/dx) = (2.5)/(-4) = -0.625

essentially the price elasticity of demand is -62.5%

for every increase of the price, the demand drops by 62.5%. I think this is only true near the value x = 4

Answer 33

Wow thank you so much ! :) I have been stuck in that problem for the longest.

Answer 34

np