The question is as under:
Find the relative error in Z if
- Z= A/B
Relative error in A is ΔA/A and in B is ΔB/B
My solutions are :
- As A and B are being divided the relative error in Z is the sum of the relative errors in A and B.
ΔZ/Z = ΔA/A + ΔB/B
- B is raised to power -1. Then the relative error in Z will be ΔZ/Z = ΔA/A - ΔB/B
I have written - ΔB/B because when a physical quantity is raised to a power then the relative error will be the product of power and the relative error in the original quantity.
Now the cases 1 and 2 give the same meaning but the relative errors are different. Why is this so.
Please give me the explanation.