T991 Scientific Calculator is a versatile tool designed for students and engineering enthusiasts, offering a comprehensive set of features. This app emulates the functionality of the CASIO FX991 physical calculator, providing a familiar experience for users.

With T991 Scientific Calculator, users can perform a wide range of calculations including percentage, powers, roots, trigonometric functions, logarithms, linear algebra, calculus, and complex numbers. The app also supports displaying results in both rectangular and polar coordinates, along with matrix and vector operations.

Moreover, the calculator includes an equation solver capable of solving quadratic, cubic equations, and systems of equations. Additional features such as undo, history, copy/paste functionality, random integers, fraction calculations, combination and permutation, and various statistical functions make it a comprehensive tool for mathematical tasks.