Let a, b and be three non-zero vectors such that b and are non-collinear if a+5 b is collinear with , b+6 is collinear with a and a+α b+β = 0, then α…
JEE Main 2024 — Mathematics Vectors & 3D Geometry
2024mcqeasy
Let a,b and c be three non-zero vectors such that b and c are non-collinear if a+5b is collinear with c,b+6c is collinear with a and a+αb+βc=0, then α+β is equal to
Official previous-year question
Held on 29 Jan 2024 · Verified 6 Jul 2026.
Options
A
35
B
30
C
−30
D
−25
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Solution
Given: a+5b is collinear with c,b+6c is collinear with a and a+αb+βc=0.
⇒a+5b=λc...(i)
⇒b+6c=μa...(ii)
⇒a=λc−5b=μb+6c
⇒λc−5b=μ6c+μ1b
Comparing both the sides,
⇒μ=5−1,λ=−30
Putting these values in equation (i)
⇒a+5b=−30c
⇒a+5b+30c=0
Comparing this equation with a+αb+βc=0.
⇒α=5,β=30
⇒α+β=35
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