Halcyon Calc Lite vs HP

For students, engineers, scientists or people who fondly remember classic calculators, Halcyon Calc Lite is a great application for manipulating numbers and even symbolic expressions. Features: - Use this calculator on an iPhone, iPod Touch or an iPad - Use your finger to quickly scroll through the stack to review intermediate results - Copy and paste support - Over 225 built-in operations, including trig, logarithms, real functions, complex operations and more - Allows you to work with real, complex and integer numbers. - Real and complex numbers can be displayed in standard, fixed, scientific and engineering format - Integer numbers can be displayed in decimal, hexadecimal, octal and binary bases - Work with real and complex matrices and vectors - Enter symbolic expressions and solve them for different values. Even better, solve quadratic formulas, collect and expand factors and terms, find minima, maxima and roots of any expression. - Plot symbolic expressions in X/Y coordinates. Pan the coordinate space by dragging the plot in any direction. Zoom in and out using a pinch gesture. - Determine symbolic derivative, taylor series or numeric integral of an expression. - Store numbers, lists, strings and expressions in symbols. - Store statistical data and calculate totals, averages, standard deviations, linear regressions, etc over that data. - Calculate the probabilities associated with standard distributions like the normal, F and T distributions.

The classic Hewlett Packard RPN (Reverse Polish Notation) calculators. - HP-35, HP-45. First pocket scientific calculators (1972).  - HP-21. 2nd gen of the HP-35 (1975)