## Delta: Math helper

The new math app for students! Discover and create your algorithms to play with maths, with a natural and easy-to-use language.

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### Math expressions syntax

#### Numbers

Numbers from `0` to `9` can be used in maths expressions.

Examples: `2`, `32`, ...

#### Variables

Variables are a letter from `a` to `z` or a letter of greek alphabet. Warning: name can be only one character long!

Examples: `a`, `x`, ...

#### Variables with an index

You can give an index to a variable using an `_` (underscore) after the name. An index can be only one number or one letter.

Examples: `x_1`, `x_2`, ...

#### Functions

Variable can be also a function of a variable if you name it like `f(x)`. Then you can use it with any expression like `f(2)`.

Examples: `f(x)`, `g(z)`, ...

#### Operations

What would be maths without operations between numbers? You can use classic operations: `+` (addition), `-` (subtraction), `*` (multiplication) and `/` (division).

Examples: `x + 1`, `1 / x`, ...

#### Hidden multiplications

Want to write `2x` instead of `2 * x`? You can! Delta: Math helper supports hidden multiplications.

Examples: `2x`, `x(x + 1)`, ...

#### Powers and square roots

You can also use `^` (power) and `√` (square root) in your expressions. If the expression after the operation sign is a composed expression, please add `()` (braces) to it. (see examples)

Examples: `x ^ 2`, `2√2`, `√(x+1)`, ...

#### Modulo

Modulo (remainder of a division) is available with `%`. For exemple, `5 % 2` will return `1` because `5 = 2 * 2 + 1`.

Examples: `5 % 2`, `a % b`, ...

#### Equations

Having two expressions seperated with an equation operator will be considerated as an equation. You can use `=` (equals), `!=` (unequals), `>` (greater than), `<` (less than), `>=` (greater than or equals) and `<=` (less than or equals).

Examples: `x = 2`, `2a < 5`, ...

#### Lists and sets

You can create a list/set of expressions using `{}`, separating expressions with `,` (coma).

Examples: `{2, 4, 6}`, `{x, 2x, 3x}`, ...

### Create algorithms

#### Variable: Ask for `variable` with default `value`

Create a cell to set a value to the variable for algorithm process.

Example: Ask for `a` with default `1`

ParameterRole
`variable`Variable name
`value`Default value in the cell

#### Variable: Set `variable` to `value`

Set the value of the variable when called.

Example: Set `n` to `n + 1`

ParameterRole
`variable`Variable name
`value`Value given to the variable

#### Structure: If `condition` ... Else ... End

If the condition is true, the code between If and Else will be executed. Else, the code between Else and End will be executed.

Example: If `a = 1` ... Else ... End

ParameterRole
`condition`The equation that will be checked

#### Structure: While `condition` ... End

The code between While and End will be repeated while the condition is true.

Example: While `a < 10` ... End

ParameterRole
`condition`The equation that will be checked

#### Structure: For `variable` in `list` ... End

The code between For and End will be repeated for each value of the list, available in a variable.

Example: For `x` in `{0, 1, 2}` ... End

ParameterRole
`variable`The variable containing the current value
`list`The list of values to iterate

#### Output: Print variable `variable`

Print in a cell the value of the variable or the expression.

Example: Print variable `x`

ParameterRole
`variable`Variable name or expression

#### Output: Print text `text`

Print in a cell the given text. You can use `""` to print a variable in the text.

Example: Print text `"n" is even`

ParameterRole
`text`Text to be printed