Knowledge Base

Solution 21911: nDeriv and Derivative Commands Use Different Algorithms to Compute Answers.

Do the nDeriv and derivative commands use different algorithms to compute answers? If so, which answer is more accurate?

The nDeriv() and Derivative commands are based on different algorithms. While the Derivative command solves for the derivative of the function exactly, the nDeriv() command uses the following formula:

(f(var+step) - f(var-step))/(2*step)

Please Note: On the TI-86, replace 'step' with the tolerance variable.

In general, the derivative command is more accurate than the nDeriv command with the default step/tolerance (.001 by default).