Integral

Prerequisites Derivative

Those videos are really enough for understanding

Integration and fundamental Theorem of Calculus Integration and fundamental Theorem of Calculus

Derivative's slope and Integral's area Derivative’s slope and Integral’s area

Area under curve The area under the curve is the integral

Single nudge of the area a single nudge of the area

Mean of the derivative the mean of the derivative

Secant is the mean of tangentials Secant is the mean of tangentials