The angle made by a vector $\overrightarrow{\mathrm{B}}=3 \hat{\mathrm{i}}+2 \hat{\mathrm{j}}+4…
The angle made by a vector $\overrightarrow{\mathrm{B}}=3 \hat{\mathrm{i}}+2 \hat{\mathrm{j}}+4 \hat{\mathrm{k}}$ with $\mathrm{y}$ -axis is
$\cos ^{-1}\left(\frac{5}{\sqrt{23}}\right)$
$\cos ^{-1}\left(\frac{4}{\sqrt{11}}\right)$
$\cos ^{-1}\left(\frac{3}{\sqrt{17}}\right)$
$\cos ^{-1}\left(\frac{2}{\sqrt{29}}\right)$
Solution
$\begin{array}{l}
\vec{B}=3 \hat{\imath}+2 \hat{\jmath}+4 \hat{k} \\
y \text {-axis }=\hat{\jmath}
\end{array}$
$\angle$ made with y axis
$=\cos ^{-1}\left(\frac{2}{\sqrt{29}}\right)$