Question

Given two vectors $a=2i-3j+6k$ on $b=2i+3j-k$ and $\lambda =\frac{theprojectionofaonb}{theprojectionofbona},$ then the value of $\lambda$ is

• A. 3/7
• B. 7/3
• C. 3
• D. 7

Answer 1

The correct option is B 7/3

$\lambda =\frac{theprojectionofaonb}{theprojectionofbona},$
$=\frac{\frac{a.b}{\left|b\right|}}{\frac{b.a}{\left|a\right|}}=\frac{\left|a\right|}{\left|b\right|}=\frac{7}{3}$