Complex numbers are a superset of real numbers. Complex numbers are two dimensional and is most often written on rectangular form as a+bi where a is the real part and b is the imaginary part. The imaginary unit i is defined as i^2=-1. Complex numbers can also be shown on polar form as a∠θ where a is the absolute value of the number and θ is the angle of the number in radians or degrees.

Complex numbers are used in the Evaluate dialog for standard functions and for graphing functions when Calculate with complex numbers is enabled under the Settings tab in the Edit axes dialog.

The function list is shown in the left side of the main window. This list shows a list of all functions, tangents, point series, shadings and relations. When you want to manipulate an item, you first have to select it. The selected item is normally marked in blue, but it will be marked in gray when something other than the function list has focus. You can manipulate the selected element through the Function menu or through the context menu appearing when you right click on the element.

A graph element is something that is shown in the coordinate system. This can be a function, point series, label, relation, etc. The graph elements are also shown in the function list where they can be manipulated from the Function menu or the context menu.

The set of numbers ...,-3,-2,-1,0,1,2,3,... is called integers and is a subset of the real numbers. A given integer n may be negative, zero or positive.

The legend is a box that per default is placed at the upper right corner of the graphing area, and shows a list of the plotted functions, tangents, shadings, and point series in the coordinate system. Select Show legend under Settings in the Edit axes dialog to show the legend. Right click on an item in the function list and deselect Show in legend if you don't want the item shown in the legend. When editing an item you can enter the text to be shown in the legend. For functions and tangents the function equation will be shown if no legend text is entered.

An expression that can be evaluated as a number is called a numeric expression. The expression can include any combination of numbers, constants, variables, operators and functions.

Radians are a way to describe the size of an angle similar to degrees, but radians are not a unit like degrees. The angle of a whole circle is 360° or 2π radians. An angle in radians can be converted to degrees by multiplying with 180°/π. An angle in degrees can be converted to radians by multiplying with π/180°. You can choose to use radians or degrees for trigonometric functions in the Edit axes dialog under the Settings tab.

A real number is on the form nnn.fffEeee where nnn is the whole number part that may be negative. fff is the fraction part that is separated from the integer part with a dot '.'. The fraction part is optional, but either the integer part or the fraction part must be there. E is the exponent separator and must be an 'E' in upper case. eee is the exponent optionally preceded by '-'. The exponent is only needed if the E is there. Notice that 5E8 is the same as 5*10^8.