**EQUATION** is a software for graphs of mathematical functions, which traces the functions, in 2D, on a Cartesian plane X-Y. I programmed this software when I was 15 years old: on the other hand, at the Scientific High School, mathematical functions were studied. So I had the opportunity to combine two passions, the one for computer science and the one for mathematics.

The EQUATIO mathematical function graphing software is able to plot two functions in parallel, one for each Cartesian axis. The graph is then plotted point by point.

The functions available in the EQUATIO mathematical function graphing software are included in the following list:

- ATN โ arctangent of a number;
- ABS โ absolute value of a number;
- COS โ cosine of an angle;
- SIN โ sine of an angle;
- SQR โ square root of a number;
- TAN โ tangent of an angle;
- INT โ integer value of a number;
- LOG โ logarithm of a number;
- RND โ random number generator;
- EXP โ exponential of a number;
- SGN โ sign of a number.

The software allows you to set the color of the chart, save and upload to file all the expressions typed and also the settings.

You can set the maximum and minimum limit of the independent variable, so as to plot the graph of the function only in the section of interest. The zoom function is also available, to enlarge or reduce the view of the plotted mathematical function.

Three independent variables are available in parallel, each with its own maximum and minimum limit. In addition, there is a function to color closed areas of plotted charts.

### Examples of using the software for graphs of mathematical functions EQUATIO

Below, here is an example of tracking a mathematical function on the Y axis, with a single independent variable X:

Y = sin (X) + X

This second example is related to two mathematical functions, which share the same independent variable W, which are plotted on the two axes X and Y in parallel:

X = W * cos (W)

Y = W * sin (W)

**Programming language**: Borland TurboBasic.**Project start**: January 1993. **State**: for personal use.