Calculus was created in order to calculate volume and area. Everything in our world is not able to be measured by straight lines and 90 degree angles. Its roots can be traced back the the ancient Egyptians. You can read more about the history of calculus at the link provided below.
Sir Isaac Newton. He and Leibniz both invented the calculus independently.
discovered
Newton Invented it for his theory of gravity.
Issac Newton and Gottfried Leibniz invented the calculus and argued the rest of their lives over who had the priority in this invention.
Gottfried Leibniz.
Integral calculus was invented in the 17th century with the independent discovery of the fundamental theorem of calculus by Newton and Leibniz.
Greece
Sir Isaac Newton. He and Leibniz both invented the calculus independently.
Newton and Leibniz simultaneously and independently invented calculus.
Liebniz.
discovered
Calculus was invented or rather can be detailed as back as 1820 B.C. when the Egyptians used it in order to calculate the volume of the pyramidal frustum
Newton Invented it for his theory of gravity.
If you mean "who invented calculus", then Isaac Newton and Gottfried Leibniz both developed it independently.
Calculus was invented to solve physics problems, so the importance of studying calculus is to solve physics problems.
Issac Newton and Gottfried Leibniz invented the calculus and argued the rest of their lives over who had the priority in this invention.
Izac Newton