4  Expressions

4.1  Basics

Expressions are generally entered at the rcalc prompt as you would write them down on paper.

The notable exception to this is that rcalc does not support implied multiplication: you cannot enter 3sin(2pi) as the parser will not recognize that you mean `three multiplied by the sine of two multiplied by pi'. The correct way to enter the above expression is 3*sin(2*pi).

4.2  Variables

You can assign any calculation result to a variable. To do this, just prepend your variable name and '=' to the expression, like this :

rcalc> MyVariable = 3*sin(pi/4)

The result can then be used in subsequent calculations, for example:

rcalc> e^MyVariable

Variable names, and indeed function, command and constant names, are case-insensitive: MyVariable, myvariable, MYVARIABLE and MyVaRiAbLe all refer to the same value. Any whitespace in expressions is ignored.

4.3  To define your own functions

When defining a function, the variable is x. Currently, you can only define a function that uses only 1 variable (x), that is, you cannot define something like f(x,y)=cos(x) + sin(y).

To create a new function, use the func command:

func [function_name](x)=[function_expression]


rcalc> func g(x)=2*x

rcalc> func myfunction(x) = 2*x*x + 7*cos((sin(x))) - abs(x)

Then, you can use these functions just like other built-in functions:

rcalc> g( 5 * cos ( myfunction( 2-Ans ) ) )