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t_n_p
Apr17-07, 02:27 AM
1. The problem statement, all variables and given/known data

http://img224.imageshack.us/img224/2459/untitledow9.jpg

2. Relevant equations



3. The attempt at a solution

See above picture.

I'm just curious to see if my method is correct and how exactly would I go about simplifying the answer if indeed it is correct. Thanks to anybody who can help!

daveb
Apr17-07, 03:26 AM
Your expression for the derivative of sqrt(xy) using the chain rule is in error. Y is under the square root in the expression, so the first half should be sqrt(y/x)/2. From this you should be able to get the second half.

HallsofIvy
Apr17-07, 05:37 AM
Rather than writing \sqrt{xy} as (xy)1/2, write it as x1/2y1/2. I think you will find that less confusing.

t_n_p
Apr17-07, 06:06 AM
http://img149.imageshack.us/img149/9232/workingdh2.jpg

Thanks for pointing that out, I made the relevant changes, I hope it's a bit better now. The final answer seems very, very long winded though. Am I on the right track? Hope nobody minds me posting the pictures instead, it's easier for me than doing it on the computer!

daveb
Apr17-07, 06:31 AM
Yes, you're on the right track now!

t_n_p
Apr17-07, 06:36 AM
thanks for speed reply
My final answer is......

http://img413.imageshack.us/img413/246/finalanswml7.jpg

amiright? :tongue2: