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4-1.Complex numbers
normal
$arg\,(5 - \sqrt 3 i) = $
A
${\tan ^{ - 1}}\frac{5}{{\sqrt 3 }}$
B
${\tan ^{ - 1}}\left( { - \,\frac{5}{{\sqrt 3 }}} \right)$
C
${\tan ^{ - 1}}\frac{{\sqrt 3 }}{5}$
D
${\tan ^{ - 1}}\left( { - \frac{{\sqrt 3 }}{5}} \right)$
Solution
(d)Let $z = 5 – \sqrt 3 \,i$
==> $r(\cos \theta + i\sin \theta ) = 5 – \sqrt 3 \,i$
==> $r\cos \theta = 5$and $r\sin \theta = – \sqrt 3 $
$\therefore $ $\tan \theta = – \frac{{\sqrt 3 }}{5} \Rightarrow \theta = {\tan ^{ – 1}}\left( { – \frac{{\sqrt 3 }}{5}} \right)$
Standard 11
Mathematics