Question

Truncation error is the difference between __________

(a) the exact solution of the partial differential equation and the discretized equations

(b) the exact partial differential equation and the discretized equations

(c) the exact solution and the numerical solution of the partial differential equations

(d) the exact partial differential equation and its solution

This question was addressed to me in an interview for internship.

My doubt is from Errors in Finite Difference Approximations in chapter Finite Difference Methods of Computational Fluid Dynamics

Answer 1

The correct choice is (b) the exact partial differential equation and the discretized equations

The explanation: Truncation error is the difference between the exact partial differential equation and the discretized algebraic equation. This arises as we cut-off the higher order terms in the Taylor series expansion.