Can someone tell me how to do these?

Question

Estimate INT from 0 to 1 2/(1+x^2)dx by subdividing the interval into 8 parts, using
(i) the left Riemann sum: INT from 0 to 1 2/(1+x^2)dx
(ii) the right Riemann sum: INT from 0 to 1 2/(1+x^2)dx
(iii) the trapezoid rule INT from 0 to 1 2/(1+x^2)dx