# Plot and Analyse functions with the plotXpose App available for Android

Plot functions, derivatives & integrals. Explore frequency analysis and Digital Signal Processing (DSP) concepts through graphs. Solve equations numerically using a variety of methods.

plotXpose app is a companion to the book Mathematics for Electrical Engineering and Computing by Mary Attenborough, published by Newnes, 2003.

plotXpose app is available on Google Play

Versions will shortly be available for iOS and Windows.

The app allows you to define and plot a General Function made up by a composition of any of the following standard operations and functions:

-, +, *, / , ^(power), sin, cos, tan, ln (log base e), log (log base 10), arcsin (inverse sine), arccos (inverse cos), arctan (inverse tangent). In addition a Square Wave or Triangular Wave can be defined. You can Open a previously saved function from a file.

The function is defined as a function of t (often representing time). Initially the function is defined for values of t between t = -5 and t = 5, at a sampling interval of 0.01, and the y-axis is displayed over the full range for y. These values can be changed using Settings. The function is displayed and also the exact Derivative. The Integral can also be viewed on the same axes and the Frequency spectrum is viewed in a separate tab.

To determine values on the graph use View to display a grid or Display Position, in which, tapping on the function, its derivative or integral, displays the coordinates at that location. You can Save to a file any one of the function, derivative or integral. These values can be read back into plotXpose via the Open menu item.

Equation solving can be performed using Zero Find and various numerical methods. The sequence of values found is displayed on the screen and can be saved to a file.

Tangent Mode can be used to display tangents to to any of the defined curves along with the gradient and the equation of the tangent.

There are some problems and investigations on the companion website to accompany Mathematics for Electrical Engineering and Computing for which this app can be used and Hints on Projects and Investigations are provided in this Help. In addition many of the Exercises in other chapters (e.g. graph sketching, numerical integration, sequences) can be checked with the aid of this app. Some extra suggested Problems are given in this help.