Simpson's rule spacing

hi i was wondering if someone could help me, I am learning stability and am trying to use simpson's rule but the lecturer's way of calculating the spacing between ordinates doesn't give a realistic answer. does the way of working out spacing change when half ordinates are used? thanks in advance

 

The lecturer should have given you some notes. I assume you are using the 'first' rule and not the second.

 

No. The Simpson multiplier is changed.

So if you had a series of 1,4,2,4,2,4,2,4,2,4,1 for example, but if the last 3 ords were at half spacing, then the last 4 ords would be: 4, 1 /1/2, 2, 1/2.

The last 3 ords, of 1-4-1 are now halved. But the spacing "h" remains the same.

 

ok thanks that cleared things up!