Best

I myself follow a mathematical discipline and we always learn that the square root of a^2 depends on the sign of a. For example, if a is negative, then the qq of a^2 equals -a. Now I suddenly see on Wikipedia that the vkw of a^2 is equal to the absolute value of a? What is the correct answer here?

Thanks in advance!

## Answer

Dear Thomas,

You actually already gave the answer yourself: as long as a is a real number, both answers are correct!

For a negative, the positive square root of a^2 equals -a, but then Abs(a) also equals -a.

For a positive or zero, the positive square root of a^2 equals a, and in this case Abs(a) also equals a.

The advantage of the Wikipedia answer is that you cover both answers with one function.

Abs(a) is rightly also the answer you get from a mathematical package such as Mathematica if you specify that it concerns a real number (see attached photo):

Philippe J. Roussel

Senior Reliability Researcher

IMEC â€“ ASPIRE INVENT ACHIEVE

## Answered by

#### Ing. Philippe Roussel

Microelectronics Reliability

Kapeldreef 75 3001 Leuven

http://www.imec-int.com

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