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4-1.Complex numbers
easy
સંકર સંખ્યા $z = \sin \alpha + i(1 - \cos \alpha )$ નો કોણાંક મેળવો.
A
$2\sin \frac{\alpha }{2}$
B
$\frac{\alpha }{2}$
C
$\alpha $
D
એકપણ નહીં.
Solution
(b) $z = \sin \alpha + i(1 – \cos \alpha )$
==> $amp(z) = {\tan ^{ – 1}}\left( {\frac{{1 – \cos \alpha }}{{\sin \alpha }}} \right) = {\tan ^{ – 1}}\left( {\frac{{2{{\sin }^2}\frac{\alpha }{2}}}{{2\sin \frac{\alpha }{2}\cos \frac{\alpha }{2}}}} \right)$
$ = {\tan ^{ – 1}}\tan \left( {\frac{\alpha }{2}} \right) = \frac{\alpha }{2}$.
Standard 11
Mathematics