brentbrent wrote:

Hi all

\frac{1}{2+\sqrt{3}}=?A.

\sqrt{3}-2B.

2-\sqrt{3}C.

\sqrt{2}+\sqrt{3}D.

2+\sqrt{3}E.

\sqrt{3}+4B

Solution:(2-\sqrt{3})*(2+\sqrt{3})=4-3=1

Is there a fast way to recognize which one is correct here? Or can some one elaborate on the solution?

Thanks!

edit: corrected answer choice. whoops.

Try this method instead....

we knw sqaure root of 3 is 1.732

So the equation becomes 1/(2+1.732)

that gives 1/(3.732) or may be rounded off to 1/4 or 0.25

Now working with options only B gives 2-1.732 that would give answer as 0.25.

Hope this helps.

_________________

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