CRCalc.js Exact Calculator

CRCalc.js calculator supports defining variables x, y, z, and custom functions f, g.

1. Variables x, y, z

• 1. Define variables

  1. Enter the expression you want to save in the input box, for example: 3^6
  2. Click 2ndF to enter the second function mode. The variable button will become →x / →y / →z.
  3. Click the →x / →y / →z button.
  4. Once defined successfully, the variable can be used in subsequent expressions.
  5. Click 2ndF again to exit the second function mode.

  Redefining: Repeating the above steps will override the old definition.

• 2. Use variables

  • Click the x / y / z button to insert the corresponding variable, or use the keyboard to enter the variable name.
  • Using variables for calculation. For example: x+1
  • Press = or Enter to calculate.
  • If the variable is not yet defined, an error will be raised during calculation.

2. Functions f, g

• 1. Define functions

  1. Enter the function body in the input box, using x as the parameter. For example: x^2+1
  2. Click 2ndF to enter the second function mode. The function button will become →f(x) / →g(x).
  3. Click the →f(x) / →g(x) button.
  4. Once defined successfully, you can call the function in formats such as f(2), g(3), etc.
  5. Click 2ndF again to exit the second function mode.

  Redefinition: Repeating the above steps will override the old definition.

• 2. Use functions

  • Click the f or g button to insert f( or g(, or enter the function name using the keyboard.
  • Enter the parameters and complete the right parentheses. For example: f(2)
  • Press = or Enter to calculate.
  • If the function is not yet defined, an error will be raised during calculation.

3. Notes on Custom Variables and Functions

1. When defining, all variables and functions used are inlined
   When defining a variable/function, other variables/functions appearing in the definition WILL BE DIRECTLY EXPANDED using the value/expression from the definition. After that, changing a referenced variable/function WILL NOT affect variables/functions that have already been defined.

   Example 1:

   1. Define x = 2.
   2. Define y = x + 1.
      At this point, y is INLINED as 2 + 1, i.e., y = 3.
      
   3. Redefine x = 10.
      y is still 3, it WILL NOT become 11.

   Example 2:

   1. Define x = 3.
   2. Define f(x) = x^2 + 1.
      Here, x is the function parameter and will not be inlined as 3.
      
   3. Define y = 5.
   4. Define g(x) = f(x) + y.
      At this point, g INLINES the current definitions of f and y, resulting in g(x) = x^2 + 1 + 5.
      
   5. After modifying f or y, g WILL NOT change accordingly.
2. In the function definition, x is the parameter
   • When defining a function, x in the function body is treated as a placeholder for parameters, and is NOT inlined as the variable x.
   • When calling a function, the argument replaces this x.
   • If you want to use variables in a function body, use y or z, not x, or it will be treated as parameter.
3. The order of definitions is important
   • First define the referenced variables/functions, then define new variables/functions.
   • If a variable/function that has not yet been defined is referenced in the definition, an error will be raised.
   • Since definitions are inlined, subsequent changes to base variables/functions WILL NOT automatically update already defined upper-level variables/functions.
4. Recursion is not supported
   Referencing self in function definitions WILL NOT work as expected.