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joemama142000
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joemama142000
the oa is E

1/(3-sqr2*sqrt3*2+2)=(5+2sqrt3*sqrt2)/( 25-24)= E


good question..........
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Guys,

There is simple method.

[ 1/(sqrt3-sqrt2)]^2
= [(sqrt3+sqrt2)/(3-2)]^2
= (sqrt3+sqrt2)^2
= 3+2+2*sqrt3*sqrt2
= 5+2*sqrt(6)
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Angela780
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vivek123
Guys,

There is simple method.

[ 1/(sqrt3-sqrt2)]^2
= [(sqrt3+sqrt2)/(3-2)]^2
= (sqrt3+sqrt2)^2
= 3+2+2*sqrt3*sqrt2
= 5+2*sqrt(6)


Vivek, can you explain this to me?
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vivek123
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vivek123
Guys,

There is simple method.

[ 1/(sqrt3-sqrt2)]^2
= [(sqrt3+sqrt2)/(3-2)]^2
= (sqrt3+sqrt2)^2
= 3+2+2*sqrt3*sqrt2
= 5+2*sqrt(6)

Vivek, can you explain this to me?


Sure,
[ 1/(sqrt3-sqrt2)]^2 ----------------- (1)

The denominator is (sqrt3-sqrt2), in such problems, if we can get the denominator in simpler form, great!

Multiply & divide (1) by (sqrt3 + sqrt2)

= [(sqrt3 + sqrt2)/((sqrt3 + sqrt2)(sqrt3 - sqrt2))]^2 ------------------------------- (2)

Notice that, now the denominator is in the form, (a-b)(a+b)
we know that, (a-b)(a+b) = a^2-b^2
i.e. (sqrt3 + sqrt2)(sqrt3 - sqrt2) = (sqrt3)^2 - (sqrt2)^2 = 3 - 2 = 1

Put this value in equation (2)

= [(sqrt3+sqrt2)/1]^2
= (sqrt3+sqrt2)^2

Now apply (a+b)^2 = a^2+b^2+2ab

= 3+2+(2*sqrt3*sqrt2)
= 5+2*sqrt6
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Thanks Vivek.. :-D ..

You make it seem so simple :wink:
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Professor
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vivek123
Guys,

There is simple method.

[ 1/(sqrt3-sqrt2)]^2
= [(sqrt3+sqrt2)/(3-2)]^2
= (sqrt3+sqrt2)^2
= 3+2+2*sqrt3*sqrt2
= 5+2*sqrt(6)


very good approach...........



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