Question- Why are limits used in calculus
Answer#1- In mathematics, a limit is the value that a function (or sequence) "approaches" as the input (or index) "approaches" some value. Limits are essential to calculus (and mathematical analysis in general) and are used to define continuity, derivatives, and integrals.
Answer#2- We use limit when we can not clearly order a number to express something, but , by adding more and more numbers we get closer and closer to a certain number, but do not reach it. That is when we say that we are approaching a limit.
You can whichever one you feel like using, both are correct. I hope that you and your family are well during this pandemic. Please stay home and stay safe. You have my prayers. Have a wonderful day!