$4.99 from Pierre-Henri Jondot
TouchPlot is a powerful grapher with a long list of features :
– formula editor with custom keyboards along with prettyprint display of the formula being entered. Note that the syntax being used to enter a formula is based on direct Polish notation. There is a learning curve, but usually it becomes really slick with practice. Note that there is no need to enter parenthesis with Polish notation (they get added for you), so the absence of parenthesis in the keyboard is not a bug, but a feature.
Please take the time to read the (new) embedded documentation about the editor, and visit the touchplot website for more information and tutorials.
– symbolic differentiation
– (new) numeric integration with graphical display
– (new) user-defined, easy to manage, libraries of functions
– representative curves of functions with a focus on accuracy and speed, with several modes for inspection (zeros, extrema, intersection and values, definite integration)
– calculation of first terms of iterative sequences, and graphical representation of them
– parametric curves in cartesian and polar coordinates
– (numerical) solutions of ordinary differential equations (first and second order) with vector fields
– user defined constants with sliders to observe how a curve is changed by a parameter, or to adjust initial conditions of a differential equation particular solution…
– logarithmic scales if needed, adjustable separately for horizontal and vertical axis.
– drawing of equations, inequations solutions, contourplots, gradient fields, and 3d-plotting of surfaces with equation z=F(x,y).
See the website for documentation, tutorials and activities, videos.
P.S. : here’s a hint for those who don’t know : you can get a screenshot of the current view by pressing home+lock buttons.
P.P.S. : if despite the embedded documentation and the tutorials on the website you encounter a difficulty, you can get support through email. The adress is very easy to be found in the website as well as in the embedded documentation. (See About section).