r=k(b+c)r⋅a=3r⋅a=k(b⋅a+c⋅a)3=k(2+6−15+3−2+3λ) 3=k(−6+3λ) ...(1) r=k(5i^+2j^−(5−λ)k^) ∣r∣=k25+4+25+λ2−10λ=1 ...(2) k=−6+3λ3=−2+λ1 put in (2) 4+λ2−4λ=54+λ2−10λ6λ=503λ=25
JEE Main 2024 — Mathematics Vectors & 3D Geometry
Let a=i^+2j^+3k^,b=2i^+3j^−5k^ and c=3i^−j^+λk^ be three vectors. Let r be anit vector along b+c. If r⋅a=3, then 3λ is equal to:
Held on 8 Apr 2024 · Verified 6 Jul 2026.
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