Vector Algebra Question 284

Question: If the position vectors of the points A, B, C be $ \mathbf{a},\ \mathbf{b} $ , $ 3\mathbf{a}-2\mathbf{b} $ respectively, then the points A, B, C are

[MP PET 1989]

Options:

A) Collinear

B) Non-collinear

C) Form a right angled triangle

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

  • Here $ \overrightarrow{AB}=\mathbf{b}-\mathbf{a} $ and $ \overrightarrow{AC}=(3\mathbf{a}-2\mathbf{b})-(\mathbf{a})=-2(\mathbf{b}-\mathbf{a}) $ Therefore, it is of the form $ \overrightarrow{AB}=m\overrightarrow{AC}. $ Hence A, B, C are collinear.