1. You can't divide by 0. This mathematical fact has been a favorite of teachers for years. 0 divided by any number is equal to 0 but any number divided by 0 is undefined. Although there are many ways to show why you can't divide by 0, perhaps this simple, non-rigorous example will suffice: let's divide 3 by 0 and say that the answer is "x" which is representative of some real number. In other words, 3 / 0 = x. If you cross multiply then you get (0) (x) = 3. In other words 0 = 3, which is clearly false. Don't worry if you don't understand this example... All you need to remember is that any number divided by 0 is undefined.

2. The square root of a negative number is an imaginary number. The square root of -1 is, by definition, equal to "i." Likewise the square root of -5 is equal to 5i. Unless you are studying complex (imaginary) numbers, if you get a negative number as the radicand (the number under the square root or cube root symbol), then you have probably done something wrong and should re-check your math.

3. You can take the cube root of a negative number. The cube root of -8 is equal to -2. In fact, when ever the root number is odd (e.g. cubed root, 5th root, 7th root, etc...) you can have a negative number in the radicand.

## No comments:

## Post a Comment