?
If x = 1 + $$\sqrt 2 $$ + $$\sqrt 3 $$ and y = 1 + $$\sqrt 2 $$ - $$\sqrt 3 {\text{,}}$$ then the value of $$\frac{{{x^2} + 4xy + {y^2}}}{{x + y}}$$ is?
Answer & Solution
Correct Answer:
Option
D
$$\eqalign{
& {\text{According to the question,}} \cr
& x = 1 + \sqrt 2 + \sqrt 3 \,.....(i) \cr
& y = 1 + \sqrt 2 - \sqrt 3 \,.....(ii) \cr
& \Rightarrow \frac{{{x^2} + 4xy + {y^2}}}{{x + y}} \cr
& \Rightarrow \frac{{{{\left( {x + y} \right)}^2} + 2xy}}{{x + y}} \cr
& {\text{From equation (i)}} + {\text{(ii)}} \cr
& \Rightarrow x + y = 2 + 2\sqrt 2 \cr
& xy = {\left( {1 + \sqrt 2 } \right)^2} - {\left( {\sqrt 3 } \right)^2} \cr
& \Rightarrow xy = 3 + 2\sqrt 2 - 3 \cr
& \Rightarrow xy = 2\sqrt 2 \cr
& {\text{So, }}\frac{{{{\left( {x + y} \right)}^2} + 2xy}}{{x + y}} \cr
& = \frac{{{{\left( {2 + 2\sqrt 2 } \right)}^2} + 2 \times 2\sqrt 2 }}{{2 + 2\sqrt 2 }} \cr
& = \frac{{4 + 8 + 8\sqrt 2 + 4\sqrt 2 }}{{2 + 2\sqrt 2 }} \cr
& = \frac{{12 + 12\sqrt 2 }}{{2 + 2\sqrt 2 }} \cr
& = \frac{{12\left( {1 + \sqrt 2 } \right)}}{{2\left( {1 + \sqrt 2 } \right)}} \cr
& = 6 \cr} $$
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