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# How Do X**y and Y**x Work On iOS 7 Calculator?

One of the new apps released with iOS 7 is a calculator, and several of the functions on this calculator are exponentiation. But I am puzzled how the functions x**y and y**x work (x to the y-th power and y to the x-th power). In particular, how do we set the value of y? If this were an RPN calculator, then we could push values onto the stack For instance, with an HP calculator you would do 2 enter 3 y**x and the result would be 8, because x is 2 and y is 3. But I don’t see an obvious counterpart on the iOS 7 calculator.
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Richard Fuhr

### Comments: 2 Responses to “How Do X**y and Y**x Work On iOS 7 Calculator?”

6 years ago

Actually, that app isn’t new. It was in iOS 6, and before that as well. May even date back to the original iPhone OS, though I don’t think it had the extended functionality that you get in recent years when you turn the iPhone on its side.
For those that haven’t tried this, simply launch the Calculator app that comes built into the iPhone. You’ll see a standard simple calculator. Now turn your iPhone so it is in horizontal mode. Make sure you have orientation lock turned off, of course.
The horizontal calculator has all sorts of extra functions, similar to a simple scientific calculator. And those functions work the same as old calculators too.
So, to use the x**y (looks like an x with a small y in superscript) you simply type the first number (x), press the x**y button, then type the second number (y) and press =.
This is essentially the same as using + or any other basic function. You would type x, then +, then y, then =.
So if I type 3 x**y 2 = I get 9. Three to the power of two equals 9.
I don’t see a y**x function, but there are some others, like x√y (y to the root of x) that work the same way. x always comes first, then the function key, then y, then =. So 125 x√y 3 = gives me 5. The cube root of 125 is 5. (5x5x5=125).

Richard Fuhr
6 years ago

Thanks, Gary.

To display the y**x function, press the button labeled “2nd”.

If you do this, then the calculator will display several other mathematical functions as well.

Pressing the “2nd” button again will bring back the original set of functions, and some of the more commonly-used functions are always displayed.