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JEE Mains · Maths · STD 12 - 10. vector algebra

In a triangle \(ABC,\)  right angled at the vertex \(A,\)  if the position vectors of \(A, B\)  and \(C\)  are respectively \(3\hat i\, + \hat j\, - \hat k,\,\, - \hat i\, + 3\hat j\, + p\hat k\)  and \(5\hat i\, + q\hat j\, - 4\hat k,\,\) then the point \((p, q)\)  lies on a line

  1. A making an obtuse angle with the positive direction of \(x-\) axis
  2. B parallel to \(x-\)  axis
  3. C parallel to \(y -\) axis
  4. D making an acute angle with the positive direction of \(x-\) axis
Verified Solution

Answer & Solution

Correct Answer

(D) making an acute angle with the positive direction of \(x-\) axis

Step-by-step Solution

Detailed explanation

\(\overline{A B}=-4 \hat{i}+2 \hat{j}+(p+1) \hat{k}\) \(\overline {AC} = 2\hat i + (q - 1)\hat j - 3\hat k\) \(\overline {AB} \bot \overline {AC} \) \( \Rightarrow \overline {AB} .\overline {AC} = 0\) \(-8+2(q-1)-3(p+1)=0\) \(3 p-2 q+13=0\) \((p, q)\) lies on \(3 x-2 y+13=0\)…