If the Midpoint Rule is used on the interval [,] with n subintervals, at what x-coordinates is the integrand evaluated?

This question is incomplete, the complete question is;

If the Midpoint Rule is used on the interval [ -1, 11 ] with n = 3 subintervals, at what x-coordinates is the integrand evaluated?

the x-coordinates are; [1, 5, 19]

Step-by-step explanation:

Given that;

interval = [ -1, 11 ]

interval length = [( 11 + 1 ) / 3] = 4

so intervals are; [ -1, 3 ]  [ 3, 7 ]  [7, 11 ]

now midpoints for the intervals are the x-coordinates

[ (1 + 3) / 2 ] = 1

[ (3 + 7) / 2 ] = 5

[ (7 + 11) / 2 ] = 19

therefore the x-coordinates are; [1, 5, 19]

207/8 is the right