Note that $a$ is the smaller and $b$ is the larger of the last two numbers of your student ID$.$ For

example, your ID No is $010120372,$ then $a=2,b=7,$ which means that, $5.a=5\mathrm{.}2,8.b=8\mathrm{.}7,$

lower end point is $2$ and upper end point is $7$ in the definite integral.