Use the Z=f(X,Y) command on the Generate menu to generate a contour plot with elevation (Z) a function of X and Y.
All of the function-parsing routines in DPlot have the same basic syntax, capabilities and limitations:
Available two-side-operators are +, -, *, /, ^. Available one-side operators: sin, cos, tan, asin, acos, atan, abs(absolute value), sqrt(square root), log, logh(or log10), exp (inverse natural logarithm), cosh, sinh, tanh, rnd(random integer; argument is highest number that can be the output), fact(factorial), erf(error function), and cdf(cumulative distribution function). A complete list of available functions is shown here. These all take an argument that must be in parentheses.
By default, angular input values are in radians. You can set angles to degrees by clicking the degrees option button.
DPlot will automatically substitute "PI", "pi", or "Pi" in the function with "4*atan(1.0)"
NOTE: Be specific. DPlot does not interpret "2X" as "2*X".
Prevent divide by zero errors
If this box is unchecked, DPlot will trap divide by zero and many other math errors (e.g. logarithm of a non-positive value), report the value of x where the error occurred, and will not generate a curve. If this box is checked, when DPlot traps a math error it will shift x by a very small number and attempt the calculation again. This feature might be useful for generating curves of certain functions that would normally fail at specific values of x, e.g. sin(x)/x at x=0.