This app is for learning, practicing and touching differentiation to find points of extreme on cubic equation.
You can also learn differentiation on Web, for example,
This free program can be solved only by the following technique.
y=ax^3 + bx^2 + cx + d
y'= 3ax^2 + 2bx + c
After starting this app, the screen changes every three second to draw alternative question. Once touch the screen, the question begins.