Sigmabox app for iPhone and iPad

Sigmabox is a calculator thats feature-rich, well-designed, and fun to use. It includes features like:

- Live evaluation: just type to evaluate! Use the equals key to solve an equation in x. Will find all roots, real and imaginary, of polynomial equations in the form P(x) = 0.

- Store data in dozens of variables

- Dozens of physical constants at your fingertips from the speed of light to the Fermi coupling constant, whatever that is.

- Work with complex numbers, fractions, lists, and matrices. Pull up on the primary keyboard to select from advanced numerical, matrix, list, and probability functions.

- More than 80 built-in functions, from basic trig operations to complex features like statistical distributions and map/reduce.

- Define your own functions.

- Takes integrals, derivatives, and sum and products with sigma/pi notation.

- Classic mode: works as a read-eval-print-loop, just like a TI-84.

- Grapher: graph, pan, and zoom equations. Constrain equations to a domain. Trace, range, and intersection information with one swipe of your finger.

- Stats: create and store lists, and get summary data with a single swipe! Includes statistical tools and tests like linear regressions, z and t-tests, and chi-squared tests.

- Linear Solver: Solve systems of linear equations up to dimension 6.

- Converter: Easily convert values between common and obscure units in 14 categories.