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Question : 8 of 100
Marks:
+1,
-0
Solution:
Let
x=λa+µb, where
λ and
µ are scalars.
⇒‌‌x=λ(2−+)+µ(+2−) x=(2λ+µ)+(2µ−λ)+(λ−µ) Since,
x is perpendicular to
(3+2−).
Then,
x⋅(3+2−)=0 ⇒‌‌3λ+8µ=0 Also, given projection of
x on
a is
‌.....(i)
∴‌=‌ ⇒2(2λ+µ)+(λ−2µ)+(λ−µ)=51 6λ−µ=51 ...(ii)
From Eqs. (i) and (ii),
λ=8,µ=−3 ∴‌‌x=13−14+11 ⇒‌‌|x|=√(13)2+(−14)2+(11)2 ∴‌‌|x|=(13)2+(−14)2+(11)2=486
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