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The equation of line passing through the points (2, -1, 3) and (4, 2, 1) is

(A) x−22=y+13=z−3−2\frac{x-2}{2} = \frac{y+1}{3} = \frac{z-3}{-2}

(B) x−43=y−2−2=z−12\frac{x-4}{3} = \frac{y-2}{-2} = \frac{z-1}{2}

(C) r⃗=(2i^−j^+3k^)+λ(2i^+3j^−2k^)\vec{r} = (2\hat{i}-\hat{j}+3\hat{k}) + \lambda(2\hat{i}+3\hat{j}-2\hat{k})

(D) x−4−2=y−2−3=z−12\frac{x-4}{-2} = \frac{y-2}{-3} = \frac{z-1}{2}

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 1

Direction ratios are (4−2, 2+1, 1−3)=(2,3,−2)(4-2,\,2+1,\,1-3)=(2,3,-2).

(A) uses point (2,−1,3)(2,-1,3) with these ratios, so it is correct; (C) is the same line in vector form.

(D) uses point (4,2,1)(4,2,1) with ratios (−2,−3,2)(-2,-3,2), a scalar multiple, so it is also correct.

(B) has ratios (3,−2,2)(3,-2,2), which are not proportional, so it fails.

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