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sqrt(16) - how many answers?

By Murray Bourne, 21 Sep 2005

I had a heated debate with some colleagues yesterday when I claimed that √16 = 4. They were strongly advocating that there are 2 answers, ±4.

I pointed out that there is a difference between this question:

Solve for x: x2 = 16

and this question:

Evaluate x: x = √16.

The first has 2 solutions, the second has one answer.

See the 39 Comments below.

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HTML: You can use simple tags like <b>, <a href="...">, etc.

To enter math, you can can either:

  1. Use simple calculator-like input in the following format (surround your math in backticks, or qq on tablet or phone):
    `a^2 = sqrt(b^2 + c^2)`
    (See more on ASCIIMath syntax); or
  2. Use simple LaTeX in the following format. Surround your math with \( and \).
    \( \int g dx = \sqrt{\frac{a}{b}} \)
    (This is standard simple LaTeX.)

NOTE: You can mix both types of math entry in your comment.


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