Curves can be defined mathematically using the curve calculator.
The curve calculator is displayed on the Define Curves
panel when Math is selected as the data source for a vector. The
curve calculator is formatted much like a scientific calculator. It consists of a number
pad, basic algebraic and trigonometric functions, and, curve fitting, filtering, and
signalprocessing functions.

Type an expressions directly into the vector field or enter it by clicking
selected numbers, functions, or operators on the curve calculator.
Note: The curve calculator is formatted much like a scientific calculator. It
consists of a number pad, basic algebraic and trigonometric functions, and
curve fitting, filtering, and signalprocessing functions.

Once the expression is constructed, click Apply to plot
the curve.