Question

If the vectors P=ai + aj +3 and
© = ai-29 - † are perpendicular to each other
then the positive value of 'a' is
1) Zero 2 1 3 2 4) 3​

Answer 1

Answer:

Explanation:

Dot products is zero solve eqn andget ans

Answer 2

Answer:

4) 3

Explanation:

Given

$P=ai+aj+3k\\\\Q=ai-2j-k\\\\Given\;\; P\;\;and\;\;Q\;\;are\;\;Perpendicular\\\\=>\;\;P.Q=0\\\\(ai+aj+3k).(ai-2j-k)=0\\\\a^2-2a-3=0\\\\a^2-3a+a-3=0\\\\a(a-3)+1(a-3)=0\\\\(a-3)(a+1)=0\\\\a>0\\\\=>a+1>0\\\\=>a-3=0\\\\a=3$

Hope it Helps