JEE 2023 Mathematics PYQ — Let be the set of all for which the vectors , and , where , are c… | Mathem Solvex | Mathem Solvex
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JEE 2023 — Mathematics PYQ
JEE | Mathematics | 2023
Let S be the set of all (λ,μ) for which the vectors λi^−j^+k^, i^+2j^+μk^ and 3i^−4j^+5k^, where λ−μ=5, are coplanar, then ∑(λ,μ)∈S80(λ2+μ2) is equal to:
Choose the correct answer:
A.
2130
B.
2210
C.
2290
(Correct Answer)
D.
2370
Correct Answer:
2290
Explanation
Step 1: Coplanarity ki condition
Teen vectors tab coplanar hote hain jab unka Scalar Triple Product zero ho. Iska matlab unke coefficients se bana determinant zero hona chahiye:
λ13amp;−1amp;2amp;−4amp;1amp;μamp;5=0
Step 2: Determinant ko solve karna
λ(10−(−4μ))−(−1)(5−3μ)+1(−4−6)=0
λ(10+4μ)+(5−3μ)−10=0
10λ+4λμ−3μ−5=0—(i)
Step 3: Di gayi equation ka upyog
Humein sawal mein diya gaya hai ki λ−μ=5, yani λ=μ+5. Is value ko equation (i) mein rakhte hain: