Rationalizing the Denominator

boseph158

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Jun 11, 2010
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All I need help with is getting started, it has been awhile since I've done one of these problems. Thanks.

(1)/(1+sqrt(3)-sqrt(5))
 
11+35\displaystyle \frac{1}{1+\sqrt{3}-\sqrt{5}}


Multiply top and bottom by 215+5+33+7\displaystyle 2\sqrt{15}+\sqrt{5}+3\sqrt{3}+7

This will eliminate the radicals in the denominator.
 
My way.\displaystyle My \ way.

11+3513+513+5 = 13+52157\displaystyle \frac{1}{1+\sqrt3-\sqrt5}*\frac{1-\sqrt3+\sqrt5}{1-\sqrt3+\sqrt5} \ = \ \frac{1-\sqrt3+\sqrt5}{2\sqrt{15}-7}

Hence, 13+52157 215+7215+7 = 7+33+5+21511\displaystyle Hence, \ \frac{1-\sqrt3+\sqrt5}{2\sqrt{15}-7}* \ \frac{2\sqrt{15}+7}{2\sqrt{15}+7} \ = \ \frac{7+3\sqrt3+\sqrt5+2\sqrt{15}}{11}
 
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