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Formula Calculator for iPhone

Index > Creating functions

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Functions are a way of representing sets of mathematical operations. There are many standard functions available but you can also create your own and export them.

To define a function type its name with one or more parameters separated by commas followed by the expression to be evaluated. You can choose any name for your function but it has to be unique (that is, there is no other function with the same name). Function definitions should not have line breaks in them (as occur when you press Return). Lines that wrap to the next line are allowed.

Here are two examples of functions:

mySine(x)=sin(x*pi/180)

multifunc(this,that,those)=pow(this,that)-those*mySine(that)+3/2

Functions can use constants but they cannot access parameters defined outside the function. In this sense, functions are self-contained. If you want to use a parameter in the function you need to pass it through the parameter list, as in this, that and those of the example above.

Once a function is defined it can be used. Your function is automatically appended to the end of the user-functions list. It remains there while the function appears in the math text input.

To keep the function, press the Functions button, then My functions and the name of your function. You have the option of giving it a description and turning on the Keep switch.

To delete the function, just make sure it doesn't appear in the math input text. If the function has been saved for next time, press the Functions button, then My functions and the name of your function. Turn off the Keep switch.