This app will provide you a great tool if you want to plot a mathematic function.
You only have to write formula, and curve will be displayed in a customizable chart.
You can choose minimal and maximal abscissa (by default it is set from -5 to 5).
It is possible to display derivative function, so you can see both f(x) and f'(x) curves.
If you click on "VALUES" button, il shows all values between selected bounds.
You have a trace function that let you move a current point on curve, while its cordinates are displayed.
Likewise, tangent can be displayed on current point.
It can replace your scientific calculator !
Enjoy !

Examples of possible functions :
f(x) = 5x+3
f(x) = 3x^2 (equivalent to 3x²)
f(x) = 4cos(π-x)
f(x) = tan(cos(x))
f(x) = ln(x+10)
f(x) = exp(-3x) (exp is exponential function)
f(x) = xsin(x) - 6/x

Screenshots: