# First Fundamental Theorem of Calculus

- Author:
- Dr. Doug Davis, 3D

- Topic:
- Calculus

This is an illustration of the first fundamental theorem of calculus.
The graph on the left shows rectangles wide by high approximating the area under the curve at . The graph on the right is scaled to show only the additional area from to .
The slider can be used to decrease the rectangle width and the unlabeled blue point can change the location of . The points A and B can be used to change the limits of integration, ( B does not really do anything since the other point controls ).
The function can be modified by moving the black points.