How to read this formula aloud: "f(x) = x²"?

Question

f(x) = x²

Having heard this read only in Korean, I don’t know how to read it in English. What is the right English reading?

You can find a pdf-file called How to pronounce mathematical formulae in English in various places on Internet. (I was not sure, which site is most reliable and most probable to last for a long time, so I've linked to a google search instead.) — Martin, Jun 07 '14 at 15:29

score 27 · Accepted Answer · answered Jun 03 '14 at 13:30

27

It would normally be read aloud as:

f of x equals x squared

There are some variations you might hear. For example, sometimes is is used in place of equals.

If the exponent was 3, you would say cubed. Anything higher than three (say, for example, 5) would generally be read aloud as:

f of x is x to the fifth (power)

or perhaps:

f of x is x to the power of five

answered Jun 03 '14 at 13:30

J.R.

4

You can read x^4 as "x tesseracted". But okay, hardly anyone does. :-) – Jay Jun 03 '14 at 13:40
1

Some people say "f at x" instead of "f of x" – Max Jun 03 '14 at 16:28
7

@Max That's usually used for a constant: "If f of x is x squared, then f at 3 is 9." – Ypnypn Jun 03 '14 at 19:02
3

"to the power of" is the general form here - it's appropriate for any exponent, including fractions. The other versions are all short forms for (specific) whole numbers. – Brilliand Jun 03 '14 at 19:45
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@Brilliand - I agree. Moreover, the words "power of" are sometimes omitted for the sake of brevity, as in: "x to the two-thirds" or "e to the i pi". – J.R. Jun 04 '14 at 01:04
"a power of" is also fairly common, as well as "raised to the ". The omission of "power of" in the final example, however, as I would argue, is more necessary than it is optional (at least when speaking), because of how cumbersome it would become when spoken (and the meaning it loses when someone tries to parse it in their head! - would you be able to process "e to the power of the product of i and pi" quickly without stopping to think?) – Pockets Jun 04 '14 at 05:10
Powers of 2 and 3 are used so often that they have their own shorthand: "squared" and "cubed", respectively. "f of x" is understood by anyone who has had some exposure to algebra to mean "There is a function named f that takes as an input [argument, parameter] the value x." – Phil Perry Jun 04 '14 at 13:36

score 0 · Answer 2 · edited Aug 01 '18 at 11:03

0

f(x)=x² is simply read as f of x equals x squared. f being the function name and x being the input and x² serves as the output. https://www.mathsisfun.com/sets/function.html

edited Aug 01 '18 at 11:03

Mick

answered Aug 01 '18 at 08:54

J_Baltan 0619

2 Answers2