Abstract Mathematics and Friends

Postfix Logarithm Expression Evaluator

Evaluate various expressions with a small handful of operations

Enter a phrase into the main textarea. Variable fields will be automatically created.

Value:

Example Expressions

Add x and y: xy+
Subtract y from x: xy-
Take the log of x: xl
Take the antilog of x: xj
Multiply x and y: xlyl+j
Divide x by y: xlyl-j
Raise b to the xth power: bllxl+jj
nth root of x: xllnl-jj
e to the i times t: tlil+jj
Hyperbolic cosine: xj0x-j+l2l-j
Hyperbolic sine: xj0x-j-l2l-j
Cosine: xlil+jj0x-lil+jj+l2l-j
Sine: xlil+jj0x-lil+jj-l2l-il-j

Explanation

Postfix notation, also known as Reverse Polisn Notation (RPN) is a way of writing expressions so that they can be evaluated strictly from left to right. Unlike infix notation, where operators come between operands, postfix notation places its operators after the operands. Instead of writing A + B, postfix notation would write A B +. This greatly reduces the computational complexity of evaluating statements, and can eliminate confusion centered around order of operations.

This calculator is special, not because of its input method, but because it has a limited yet powerful command set. The four mathematical commands available to this calculator includes only the following:

Addition:+
Subtraction:-
Logaritm:l
Antilogarithm:j

Despite what may seem to be an over-simplified set of commands, these four are enough to multiply, divide, and take roots. If complex numbers are included, it is possible to construct trigonometric functions as well.

To make entry easier, there are a handful of defined constants understood by this calculator.

Pi:p
The imaginary unit:i
Euler's number:e
Integers 0 through 9:012...

Historically, logarithms have been used to multiply numbers before. This dates back to John Napier, a Scottish mathematician. The relationship between additions of logaritms was used in the creation of slide rules, the mechanical calculators used before the invention of the electronic pocket calculator. When multiplying large numbers with a desire for accuracy, some mathematicians would use tables of logarithm values to multiply through the addition of logs. This calculator serves to highlight the usage of logarithm techniques without using cumbersome tomes or coarsely accurate slide rules.