1) What is the problem you are having with this. Tou do know Simpson's

rule.

2) Simpson's rule reqires an odd number of points (an even number of

sub-intervals), so with h=0.25 we have 5 points, but with h=0.2 we

have 6 points so Simpson's rule is inapplicable.

3) Use the mid point rule or Euler's method

RonL