Physics | MHT CET 2020 | Discussion Page

The angle subtended by the vector $A=4\hat{i}+3\hat{j}+12\hat{k}$ with the X-axis is

$\cos^{-1}\left(\frac{3}{13}\right)$

$\sin^{-1}\left(\frac{3}{13}\right)$

$\sin^{-1}\left(\frac{4}{13}\right)$

$\cos^{-1}\left(\frac{4}{13}\right)$

Option D

Given , $A=4\hat{i}+3\hat{j}+12\hat{k}$

Also, A= A_x+A_y+A_z

$\Rightarrow$ A_x=4

The angle subtended by vector A with X- axis is

$\cos \phi=\frac{A_{x}}{|A|}=\frac{4}{\sqrt{4^{2}+3^{2}+12^{2}}}$

$\cos \phi=\frac{4}{13}$

$\phi=\cos^{-1}\left(\frac{4}{13}\right)$

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