View Full Version : Implicit Differentiation - Calculus
Janellerhiannon
Dec 4, 2008, 09:08 PM
OK, so I'm familiar with implicit differentiation, but this problem is very difficult for me to solve.
Find (dy/dx) for the equation: y = x/(x+y)
PLEASE HELP!!
galactus
Dec 4, 2008, 10:25 PM
Do you know the quotient rule?
y=\frac{x}{x+y}
y'=\frac{(x+y)-xy'}{(x+y)^{2}}
Now, solve for y' and tidy up with some algebra.
Can you finish OK?
Janellerhiannon
Dec 7, 2008, 10:05 PM
Well, I got the quotient rule part down. It's just the algebra that I'm stuck on. I keep getting different answers.
mathkid
Feb 15, 2009, 04:13 PM
You should only get one answer.
If you are solving for dy/dx, try putting all of the dy/dx's on one side of the equation, and all Xs on the other side.
Combine like multiples and then solve for dy/dx.
:D