MCQ
Given vector $\overrightarrow A = 2\hat i + 3\hat j, $ the angle between $\overrightarrow A $and $y-$axis is
  • A
    ${\tan ^{ - 1}}3/2$
  • ${\tan ^{ - 1}}2/3$
  • C
    ${\sin ^{ - 1}}2/3$
  • D
    ${\cos ^{ - 1}}2/3$

Answer

Correct option: B.
${\tan ^{ - 1}}2/3$
b
(b) $\vec{A}=2 \hat{i}+3 \hat{j}$

$A=|\vec{A}|=\sqrt{4+9}=\sqrt{13}$

$\cos \beta=\frac{y}{A}=\frac{3}{\sqrt{13}}$

$\cos \beta=\frac{3}{\sqrt{13}}$

$\sin \beta=\frac{x}{A}=\frac{2}{\sqrt{13}}$

$\operatorname{Tan} \beta =\frac{x}{y}=\frac{2}{3}$

$=\tan ^{-1}\left(\frac{2}{3}\right)$

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