Calculator 2K

Calculator2K contains large set of functions. Also, you can always add your own functions.
Comparison operations allow creating piecewise functions.
Supported by assigning a value to a variable (x ← 28), so you can use this value to other parts of the expression. Supported by characters of sums (∑) and products (∏).
You can calculate the value of the definite integral, or to plot functions.

Features:
* Creating your own functions,
* Using variables,
* History of computing,
* Calculating percent in formats 60+25% = 75 and 25%60 = 15,
* Function of cycle,
* Conditional expression,
* Enter numbers with the prefixes of decimal multipliers,
* Output of intermediate values calculation,
* Calculation of the definite integral,
* Plotting functions.

Example of creating piecewise functions:

G()←x1<-2:-4,x1<2:x1×2,4

The result of the function G(x1): for x1 less than -2 is -4, for -2 ≤ x1 <2 is x1 × 2, otherwise 4.