Q.

If the image of the point (4, 4, 3) in the line x–12=y–21=z–13 is (α,β,γ), then α+β+γ is equal to          [2025]

1 9  
2 7  
3 12  
4 8  

Ans.

(1)

Let x–12=y–21=z–13=λ

⇒ M≡(2λ+1,λ+2,3λ+1)

PM→=(2λ–3)i^+(λ–2)j^+(3λ–2)k^

Since, PM→ is perpendicular to the given line

∴  2(2λ–3)+1(λ–2)+3(3λ–2)=0

⇒ λ=1

∴   The coordinates of point M is (3, 3, 4).

Let Q be the image of the point P. Then, M be the mid-point of PQ.

∴  (4+α2,4+β2,3+γ2)≡(3,3,4)

⇒ α=2,β=2,γ=5      ∴  α+β+γ=9