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Mathematics 21 Online
OpenStudy (anonymous):

Need a quick run through on 'rationalizing denominators'. Any takers?

OpenStudy (anonymous):

depends on denominator

OpenStudy (anonymous):

\[\frac{3}{\sqrt{2}}\] use \[\frac{3}{\sqrt{2}}\times \frac{\sqrt{2}}{\sqrt{2}}\] to get \[\frac{3\sqrt{2}}{2}\]

OpenStudy (anonymous):

for example... \[6/3-\sqrt{13}\]

OpenStudy (anonymous):

or if \[\frac{x}{x-\sqrt{3}}\] use \[\frac{x}{x-\sqrt{3}}\times \frac{x+\sqrt{3}}{x+\sqrt{3}}\] to get \[\frac{x(x+\sqrt{3})}{x^2-3}\]

OpenStudy (anonymous):

ah like second example

myininaya (myininaya):

1 possibility: \[\frac{something}{\sqrt{a}+\sqrt{b}}*\frac{\sqrt{a}-\sqrt{b}}{\sqrt{a}-\sqrt{b}}\] another: \[\frac{something}{\sqrt{a}-\sqrt{b}}*\frac{\sqrt{a}+\sqrt{b}}{\sqrt{a}+\sqrt{b}}\] another: \[\frac{something}{a-\sqrt{b}}*\frac{a+\sqrt{b}}{a+\sqrt{b}}\] another: \[\frac{something}{a+\sqrt{b}}*\frac{a-\sqrt{b}}{a-\sqrt{b}}\] anohter: \[\frac{something}{\sqrt{a}}*\frac{\sqrt{a}}{\sqrt{a}}\] and the list continues....

OpenStudy (anonymous):

in your example multiply top and bottom by "conjugate" of bottom

OpenStudy (anonymous):

\[\frac{6}{3-\sqrt{13}}\times \frac{3+\sqrt{13}}{3+\sqrt{13}}\]

myininaya (myininaya):

the conjugate of a+b is a-b

myininaya (myininaya):

the conjugate of a-b is a+b

OpenStudy (anonymous):

how would you rationalize the denominator of satellite73's example?

OpenStudy (anonymous):

denominator is \[9-14=-5\] numerator is what you bet via distributive law

OpenStudy (anonymous):

how did you get -5 from the denominator : \[3-\sqrt{13}\]

myininaya (myininaya):

\[(3-\sqrt{13})(3+\sqrt{13})=3*3+3\sqrt{13}-3\sqrt{13}-\sqrt{13}\sqrt{13}=9+0-13=-4\]

myininaya (myininaya):

he made a mistake

OpenStudy (anonymous):

this is confusing

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