View Full Version : Simplifying a square root
Waggattack
Sep3-09, 10:06 PM
1.I can't figure out how the \sqrt{1+((x^2)/(4-x^2))} simplifies to 2 times\sqrt{1/(4-x^2)}
I have tried rewriting it in different ways, but I can't see how it simplifies. \sqrt{x^2 + 1/4-x^2}
The first thing to do is find a common denominator. Then you will be able to zero out some terms. Then, using the property of a square root, the square root of a fraction is the same as the square root of the numerator over the square root of the denominator. This will give you the answer.
PhaseShifter
Sep3-09, 11:12 PM
\sqrt{1+((x^2)/(4-x^2))} simplifies to 2 times \sqrt{1/(4-x^2)}
It may help to rewrite these in a form where you don't need the parentheses.
\sqrt{1+{{x^2}\over{4-x^2}}} simplifies to 2\sqrt{{{1}\over{4-x^2}}}
Does that make it easier?
Hint: 1 in the square root, 1=\frac{4-x^2}{4-x^2}
HallsofIvy
Sep4-09, 12:13 PM
In other words, write
1+\frac{x^2}{4-x^2}
as
\frac{4- x^2}{4- x^2}+ \frac{x^2}{4- x^2}
and add the fractions.
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