(MATHEMATICS) each positive number has another number that, when multiplied times itself, equals that number. So, for example, 4 has a square root of 2 (2 x 2 = 4).
The square root of a negative number is an imaginary number. Imaginary numbers are not, by themselves, useful solutions to math problems; but they can be used to find them.
BILL: Anna, we have a rectangle that's 3 x as long as it is wide, and it encloses an area of 300 square meters. What are the dimensions?
ANNA: Well, that's like 3 squares of 100 square meters. The square root of 100 is 10, so the rectangle is 10 by 30.
The logarithm of a square root is one half the log of the number itself; hence, the natural log of 25 is 3.2189, while the natural log of 5 is 1.6094.
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