Question

For the vectors $\overline{x}=(1,2,1);\overline{y}=(2,-3,-1)$ Component of $\overline{y}$ along $\overline{x}=$ _____

• A. $\frac{5}{\sqrt{14}}$
• B. $-\frac{5}{14}$
• C. $\frac{5}{14}$
• D. $-\frac{5}{\sqrt{14}}$

Answer 1

Answer: (A)

$\frac{5}{\sqrt{14}}$

Component of $\overrightarrow{x}$ along $\overrightarrow{y}$=$\frac{|\overrightarrow{x}.\overrightarrow{y}|}{|\overrightarrow{y}|}=\frac{|1\times 2-3\times 2-1\times 2|}{\sqrt{2^2+3^2+1^2}}=\frac{5}{\sqrt{14}}$