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Which of the following statements is/are TRUE?

(A) The angle between the lines whose direction ratios are proportional to (4, -3, 5) and (3, 4, 5) is 60°.

(B) If A(1,2,3) and B(2, 0, 5) are two points on a line, then its direction ratios are proportional to 1, -2, 2.

(C) The direction cosines of z-axis are 0, 0, 1.

(D) The vector equation of a line which passes through the point with position vector 3i^−j^+k^3\hat{i}-\hat{j}+\hat{k} and is in the direction of 2i^+3j^+k^2\hat{i}+3\hat{j}+\hat{k} is r⃗=(2i^+3j^+k^)+λ(3i^−j^+k^)\vec{r} = (2\hat{i}+3\hat{j}+\hat{k}) + \lambda(3\hat{i}-\hat{j}+\hat{k}), where λ\lambda is a parameter.

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 3

(A) cos⁡θ=12−12+2550=12\cos\theta = \frac{12-12+25}{50} = \frac{1}{2}, so θ=60∘\theta = 60^\circ: true. (B) direction ratios are (1,−2,2)(1,-2,2): true. (C) z-axis has direction cosines 0,0,10,0,1: true. (D) swaps the point and the direction vector, so it is false.

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