Question

What is integral all about?

Answer 1

The topic is covered in single variable calculus. The MIT course I recommend you take a look at is 18.01.

Answer 2

The area under a curve. Such as the area under the curve of y = x from 1 to 0 = 1 * 1 * 0.5 = 0.5 while another solution is \[\int\limits_{0}^{1}(x) dx = 1^2 \div 2 - 0^2 \div 2 = 1 \div 2 - 0 \div 2 = 0.5 - 0 = 0.5\]