Changing the repeat changes the reciprocal spacing. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A wider spacing has a smaller reciprocal spacing
With spacing 4 meters, the checked reciprocal is one-fourth inverse meters.
a=4m,b=1/4perm
The old reciprocal would not be allowed
The product still closes to 1; a stale one-half label is not a renderable state.