When dt is 0.00228 the curve is still ok.

When dt is 0.00385, numerical errors are creeping in. The first complete lobe has gone below the line. This suggests the results cannot be trusted.

When dt is 0.0045 numerical roundoff has become much too large.

When dt is 0.00545 numerical roundoff has gone bananas. The first complete lobe has slipped down, the next lobe is badly distorded, and the one after that is nonsense.

By dragging the slider down, you can tell when the early part of the curve starts to shift, meaning the results cannot be trusted.