This dialog box is used to add a function curve to the active plot. The function can be built with the common operators: * + / - and ^ for the power. The intrinsic functions available are listed in the appendix.

The most common way to define a function is the classical cartesian coordinate definition y=f(x), this is the defaut option. The two following parameters allow to select the x range used for the plot, and the last one is used for the number of data points that are computed in the X-range.

The functions can also be defined in a parametric definition: if *t* is the parameter, the (x,y) data points are computed by x=f(t) and y=g(t).

The first parameter is the name of the parametric variable (here *t*) followed by the range, the definition of the two functions and the number of data points.

The last way is the polar definition of the function: if *t* is the parameter, the radius *r* and the angle *theta* are computed by r=f(t) and theta=g(t). Then the (x,y) data points are computed by x=r*cos(theta) and y=r*sin(theta).

The first parameter is the name of the parametric variable (here *t*) followed by the range, the definition of the two functions and the number of data points.The angle is defined in radians, and the constant value *pi* can be used: it is possible to use 3*pi to define the parameter range.