Mathematical equation on chalkboard illustrates fundamental theorem of calculus.
A front view of a slightly smudged black chalkboard displaying a graph and several mathematical equations, all written with yellow chalk. Slightly above the center of the chalkboard, the definite integral of the function f(t), with limits of integration from a to b, is written. To the right of the integral, an equal sign connects it to the limit of a midpoint Riemann sum as n approaches infinity, a sum of the values f(c_k) times delta x_k (i. e., an area of a rectangle) from 1 to n. Below the equation, on the left side, a graph depicts a concave curve of the function f(x). The x- and y-axes are drawn with straight lines, and five ticks on the x-axis are labeled "a, x_k-1, c_k, x_k, b" accordingly. The graph shows a rectangle with a vertical line bisecting it. The line extends from the curve's intersection with the rectangle's top edge to the point c_k on the x-axis. On the right side of the graph,"F(b) - F(a)" (the fundamental theorem of calculus) is written and is vertically connected to the limit definition with an equal sign. Under the graph, the derivative of the above integral is represented by the symbol 'd/dx' and equals zero. Additional mathematical symbols are partially visible underneath. The chalkboard is mounted vertically on the white wall, with its top and bottom sections out of view in the image. The white wall is visible on both sides of the chalkboard. Indoor.