finding resistance that produces maximum power

[lmerry]

okay, this is the first time i've used this forum.. Thanks for your help in advance.

Here's the problem i'm having trouble with:

The electric power P in watts in a direct-current circuit with two resistors R1 and R2 connected in series is


v(R1)(R2)
----------------- = P
(R1 + R2)^2

where v is the voltage. If v and R1 are held constant, what resistance R2 produces maximum power?

Thanks again if you can help.

Luke

 

[tkhunny]

What do you know of the First Derivative?

 

[lmerry]

im fine on the first derivative, its basically the constants part that is confusing me. Can i somehow eliminate one of the variables?

basically i've probably just forgotten some basic algebra trick or something.