# Quick Question about uncertainty

1. Mar 14, 2005

### scissors

I'm doing a lab report right now, but am fuzzy on uncertainty in certain respects.

I have something like

d = 25 +/-2, d2 = 330 +/- 3, x = 55 +/- 6etc

how do I calculate the uncertainty, in another quantity, if it's like this

c = (d1 + d2)/x

Basically, how do I calculate the +/- part in c?

2. Mar 14, 2005

### stunner5000pt

for both multiplication and division the uncertainties are added like this

$$\frac{\Delta c}{c} = \frac{\Delta d_{1}}{d_{1}} + \frac{\Delta d_{2}}{d_{2}} + \frac{\Delta x}{x}$$