FreeGeo Mathematics PRO1.9.3 - Google Play

Dynamic geometry system for Android which optimizes interactive Geometry, Algebra, Statistics and Analysis for the touchpad and contains hundreds of powerful features. Free Geo won the german price "Preis des Bundespräsidenten Jugend forscht 2013".

Create geometric constructions and move, scale or rotate them with one or more fingers.
With the Freehandmode you can additional build your lines, circles, squares, rectangles and many more by drawing them on the screen. The system will detect it and create the object for you! For example, you can draw a freehand circle through three given points to create their circum circle.
Furthermore, you can create even complicated mathematical projects by using one of 70 tools to add different points, circles, lines (Perpendicular bisectors, Orthogonal lines, Tangents, etc.), conics, angles, functions and many more.

Define functions and parameter curves to display, integrate or derive them. Create analytical objects like tangents and circles of curvatures or combine your creation with sliders, text and check boxes. Even exact calculations are possible with the own FreeGeo Computer-Algebra-System, for example solving equations.

FreeGeo can be used in other sciences, too. You can do statistical calculations by using one of the regression methods to interpolate given data points. And it is a nice app for learning for school!

A manual of FreeGeo can be found here: http://www.freegeo.de/