Solve Wheatstone Bridge: Homework Statement & Equations

[I'mlost]

Homework Statement

I think I got part A. I'm complete lost with b -d and help would be great

Homework Equations

https://www.physicsforums.com/attachment.php?attachmentid=10986&d=1190644998

The Attempt at a Solution

It think part d is ∆V = [(∆R1 - ∆R2 + ∆R3 –∆R4 ) / 4R ] * Vo But I'm not sure

Homework Equations

The Attempt at a Solution

 

[Astronuc]

See if this explanation helps - http://en.wikipedia.org/wiki/Wheatstone_bridge

In parts b-d, R4 = R + $\Delta R$, and R1 = R2 = R3.

Find an expression for V₀ in terms of R1, R2, R3 and R4, then substitute in the appropriate values.

In part d, one is looking for how much V₀ changes as $\Delta R$ changes.