Question

If R is the total resistance of three resistors, connected in parallel, with resistances R1, R2, R3,
then
1
R
=
1
R1
+
1
R2
+
1
R3
.
If the resistances are measured in ohms as R1 = 25Ω, R2 = 40Ω, and R3 = 50Ω, with a
possible error of 0.5% in each case, use linear approximation to estimate the maximum error
in the calculated value of R

Answer 1

Take your resistance and calculate each at 99.5% and each at 100.5%. Calculate the difference and this will give you the absolute error. If you calculate R then you can use this to calculate % error by dividing your absolute error by R and multiplying by 100.

Answer 2

PS: What you need to do is calculate each this way R1@99.5%, R2@ 99.5% R#@ 99.5%. Calculate R for this and then calculate each R 2 100.5%.