Question

Write the direction ratio's of the vector $\overrightarrow{a}=\hat{i}+\hat{j}-2\hat{k}$ and hence calculate its direction cosines.

Answer 1

$\overrightarrow{a}=\hat{i}+\hat{j}-2\hat{k}$

$\left|a\right|=\sqrt{1+1+4}=\sqrt{6}$

$Directioncosines=(\frac{ax}{a},\frac{ay}{a},\frac{az}{a})ie(\frac{1}{\sqrt{6}},\frac{1}{\sqrt{6}},\frac{1}{\sqrt{6}})$

Direction ratio = (1,1,-2)