Help to solve, please, the 12th example?

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1 Answer
May 22, 2018

# sqrt2#.

Explanation:

Observe that, #sqrt(2+sqrt3)=sqrt(2+2sqrt(3/4))={2+2sqrt(3/4)}^(1/2)#,

#={(3/2+1/2)+2*sqrt(3/2)*sqrt(1/2)}^(1/2)#,

#={(sqrt(3/2))^2+(sqrt(1/2))^2+2*sqrt(3/2)*sqrt(1/2)}^(1/2)#,

#=[{(sqrt(3/2)+sqrt(1/2)}^2]^(1/2)#,

#=(sqrt(3/2)+sqrt(1/2))#.

#:. sqrt2+sqrt(2+sqrt3)=sqrt2+(sqrt(3/2)+sqrt(1/2))#,

#=(2+sqrt3+1)/sqrt2#,

#rArr sqrt2+sqrt(2+sqrt3)=(3+sqrt3)/sqrt2#.

Hence, #x=(2+sqrt3)/(sqrt2+sqrt(2+sqrt3))#,

#=(2+sqrt3)*sqrt2/(3+sqrt3)#,

#=(2+sqrt3)*sqrt2/(3+sqrt3)xx(3-sqrt3)/(3-sqrt3)#,

#={(2+sqrt3)sqrt2(3-sqrt3)}/6#

#={(2+sqrt3)sqrt2*sqrt3(sqrt3-1)}/6#,

#=sqrt6/6(3+sqrt3-2)#.

#rArr x=sqrt6/6(1+sqrt3)#.

Similarly, #y=(2-sqrt3)/(sqrt2-sqrt(2-sqrt3))#,

#rArry=sqrt6/6(sqrt3-1)#.

#:." The Reqd. Value"=x+y#,

#=sqrt6/6{(1+sqrt3)+(sqrt3-1)}#,

#=sqrt2#.