Question
Discuss the process of combination of errors when two physical quantities are multiplied.
Solution
Combination error when two quantities are multiplied, is given by
Let X = AB
Let ∆A, ∆B and ∆X be the absolute errors in A, B and X respectively.
Therefore the above equation with error can be written as, 
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are small quantities.
Therefore the product 
will be very small and hence can be neglected.
Thus the above equation reduce to,
Maximum value of fractional error in X is 
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i.e. Maximum possible %age error in X = Maximum possibe %age error in A + Maximum possible %age error in B.
