SSC CHSL Model Paper 15

Question : 68 of 100

Marks: +1, -0

a^2+b^2+c^2+

1/a^2+1/b^2+1/c^2=6

, then what is the value of

a^2+b^2+c^2

Solution:

a^2+b^2+c^2+

1/a^2+1/b^2+1/c^2=6

⇒(a^2+1/a^2-2)

+(b^2+1/b^2-2)

+(c^2+1/c^2-2)=0

⇒(a-1/a)^2+(b-1/b)^2

+(c-1/c)^2=0

∴a-1/a=0⇒a^2-1=0

⇒a^2=1

b-1/b=0

⇒b^2-1=0

⇒ b^2=1

c-1/c=0

⇒c^2-1=0⇒c^2=1

∴ a^2+b^2+c^2

=1+1+1=3

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