Graphmatica provides several styles of background graph paper to enhance the different types of graphs it can draw. Since Graphmatica allows you to put equations of all types on the screen at once, it does not attempt to guess what kind of graph paper you prefer for each graph you enter. But you can easily switch between styles using the Graph Paper item under the Options menu.

Besides the default rectangular coordinate paper, you can also select the following styles:

**Polar paper** Lined with radiating circles and straight lines at angles of +/- pi/6 and pi/3 (i.e. every 30 degrees). The traditional choice for polar and some parametric graphs. Select by marking the Polar radio button. (Note that polar and rectangular paper look the same when you set the grid detail level to none.)

**Trig paper** Rectangular grid, but x-axis is marked in multiples of pi to make it easier to work with trigonometric functions. Select by marking the Trig paper radio button.

**Logarithmic** Scales one or both axes logarithmically, so that, for instance, 0.1, 1, and 10 are equally spaced. You can set the base and switch between semi-log and log-log using the Log Options tab. If you are using base 10, you will see 9 lines per decade just like real graph paper if there is enough space to display them (generally when less than four decades are shown). Otherwise, the graph paper will look just like normal, with gridlines at integer powers of the base.

You can also control the level of detail of the grid on your graph paper. There are four possibilities:

None | No gridlines are drawn |

Reference Dots | Show dots where the gridlines would cross |

Gridlines | Dashed lines like real graph paper; this is the default |

Solid lines | Same as the above, except the lines are solid |

You can control the following "decorative" aspects of the graph paper using the check boxes in the lower-right corner of the dialog box. By default all of these options are selected. If you prefer a grid with less decoration, you can turn some of them off:

Draw Border | Check to draw a border around the grid |

Draw Axes | Draw x and y axes when they are on-screen |

Arrows on Axes | Draw arrows in the positive direction at the end of the axes. Will not appear unless Draw Axes is checked also. |

Remember that even with Draw Axes turned off, legends may still be displayed along the invisible axes unless you turn them off independently using the Legends option.

When you change the style of graph paper, the screen is redrawn immediately. Usually, all of the graphs on it are redisplayed as well, but when you switch to or from log paper, the shapes of the graphs change also, so they must be recalculated. Thus, only the number of graphs you have specified for AutoRedraw will be redrawn automatically after changing to or from log paper.

Since the logarithm of negative numbers is not defined, when you switch to log paper Graphmatica will sometimes have to alter the range displayed. If the low end of the range is below zero, it will be reset to approximately 6-8 major separations below the high end of the range. If the high end of the range is also below zero, you will be required to modify the range yourself before proceeding.

The style of graph paper that you are currently using is recorded when you save a graph document with setup information included, and the appropriate graph paper is automatically displayed when you load the file again (see POLAR.GR, TRIG.GR, and DIFEQ.GR for use of this feature).

Note that the default graph paper saved in GRAPHMAT.INI does not change unless you check the box "**Make graph paper settings the default for all graph documents**". Checking this box also saves the current log paper and legends options as the new defaults.

kSoft, Inc. ksoft@graphmatica.com Last updated: Sun 11 Jun 2017