Anti-derivative is consider as the reverse process of differentiation, which, for a given derivative essentially recovers the original function. Anti-derivative has many uses. For example, it is used by a physicist who knows the velocity of a particle to know its position at a given time. And an engineer who can measure the variable rate at which the water is leaking from a tank wants to know the amount leaked over certain time period. In each case, the problem is to find a function $F$ whose derivative is a known function $f$. If such a function $F$ exists, it is called an anti-derivative of $f$. In this section we will be studying more about anti-derivatives.