SSC CGL Model Paper 15

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Question : 65 of 100

Marks: +1, -0

If

x=a^2+b^2;

y=√2ab,

find

{a^4+b^4}/{a^2-ab√2+b^2}

$x+y$
$x-y$
$x y$
$2xy$

Solution:

x=a^2+b^2

Squaring both side,

x^2=(a^2+b^2)^2

x^2=a^4+b^4+2a^2b^2

.....(i)

y=√2ab

y^2=2a^2b^2

.....(ii)
from (i) and (ii)

x^2=a^4+b^4+y^2

x^2-y^2=a^4+b^4

∴{a^4+b^4}/{a^2-ab√2+b^2}

={x^2-y^2}/{x-y}=x+y

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