Solving equations, system of equations, integrals, primitive, limited, For secondary school students, students and teachers. For example illustrates how to use: Solving equations, no equation: x ^ 2 +3 x +2 = 0 solve. System of equations: x ^ 2 + y ^ 2 = 0, xy + x + y = 3 Solve. Graphing: sin plot. Originally function: int xlnx. Integral: xlnx, 1. E int.