1. Nov 29, 2009

### mhrobson

I need to derive the following equation with respect to R3. This is the equation for a Wheatstone bridge. Unfortunately I am not very good at derivations. Here is the equation:
VO=((R3/(R2+R3))-(R4/(R1+R4)))VS

I came up with the following answer but was told that it is wrong:
dVO/dR3 = ((1/(R2+R3))-(R3/(R2+R3)2)VS

If you want to be a real sport, set R1=R3 and derive the same expression.

2. Nov 29, 2009

### g_edgar

Suppose $$y=((x/(12+x))-(4/(12+4)))\cdot 6$$, can you do dy/dx now?