We will approximate the average value of {{MATH_100}} on the interval {{MATH_101}} with the average of {{MATH_102}}, {{MATH_103}}, {{CMD_104}}, and {{MATH_105}}: {{MATH_106}} Multiply this last expression by {{MATH_107}}: {{ENV_108}} where {{MATH_109}}. Ah! On the right we have a Riemann Sum!