Keerthana
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If x=3+22x=3+2 sqrt{2}, then the value of (x1x)left(sqrt{x}-frac{1}{sqrt{x}} ight) is :

a

1

b

333 sqrt{3}

c

2

d

222 sqrt{2}

Answer : Option C
Explanation :

x=3+22x=3+2 sqrt{2}

1x=13+22 herefore frac{1}{x}=frac{1}{3+2 sqrt{2}}

=13+22×322322=frac{1}{3+2 sqrt{2}} imes frac{3-2 sqrt{2}}{3-2 sqrt{2}}

=32298=322=frac{3-2 sqrt{2}}{9-8}=3-2 sqrt{2}

(x1x)2=x+1x2 hereforeleft(sqrt{x}-frac{1}{sqrt{x}} ight)^{2}=x+frac{1}{x}-2

=3+22+3222=4=3+2 sqrt{2}+3-2 sqrt{2}-2=4

x1x=2 herefore sqrt{x}-frac{1}{sqrt{x}}=2

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