- #1
qorizon
- 5
- 0
Homework Statement
[/B]
a=12.26 +/- 0.08
b=0.25 +/- 0.05
e=1.2 +/- 0.2
Evaluate the uncertainty of following calculations
Part 1. z= 5(ab/e)
Part 2. p= 3e - b
The Attempt at a Solution
I attempted part 1 like this
Δz/z = 5 (Δa/a + Δb/b + Δe/e)
...
Calculated Δz to be 20 but the answer is
Δz/z = (Δa/a + Δb/b + Δe/e)
...
Δz = +/- 5 (to 1 sf)
Then I saw part 2's answer like this:
Δp = 3Δe + Δb
...
Δp= +/- 0.7 (to 1 sf)
Now I'm confused. Why is it that in part 1 the constant 5 in not taken into account when calculating uncertainty, but in part 2 the constant 3 is included? Am I doing it wrong?