Question 1119299
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Expressions with zero denominators do not exist (DNE).  In other words, they do not represent any real number. Expressions with radicands (expressions under a radical sign) that are less than zero are complex numbers and are not included in the set of real numbers. Hence, in order for the given expression to represent a real value, you must exclude values for *[tex \Large x] that are the elements of the set:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \{x\ \in\ \mathbb{R}\ |\ x\ +\ 2\ \leq\ 0\}]


Which is to say:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \{x\ \in\ \mathbb{R}\ |\ x\ \leq\ -2\}]


To rationalize the denominator in an expression of the form *[tex \Large \frac{a}{\sqrt{b}}], multiply the fraction by 1 in the form of *[tex \Large \frac{\sqrt{b}}{\sqrt{b}}], thus:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \(\frac{a}{\sqrt{b}}\)\(\frac{\sqrt{b}}{\sqrt{b}}\)\ =\ \frac{a\sqrt{b}}{b}]
								
								
John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
<img src="http://c0rk.blogs.com/gr0undzer0/darwin-fish.jpg">
*[tex \Large \ \
*[tex \LARGE \ \ \ \ \ \ \ \ \ \  
								
{{n}\choose{r}}

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