Find-the-modulus-of-a-complex-number-Z-cos-40-i-sin-20-1-

Question Number 146778 by mathdanisur last updated on 15/Jul/21

F i n d t h e m o d u l u s o f a c o m p l e x

n u m b e r :

Z = c o s 40 + i s i n 20 + 1 = ?

Answered by mathmax by abdo last updated on 15/Jul/21

40 \to \frac{40 π}{180} = \frac{2 π}{9} and 20 \to \frac{20 π}{180} = \frac{π}{9} \Rightarrow Z = \cos (2 \frac{π}{9}) + 1 + isin (\frac{π}{9})

= 1 + \cos (\frac{2 π}{9}) + isin (\frac{π}{9}) \Rightarrow∣ Z ∣= \sqrt{(1 + \cos {(\frac{2 π}{9})}^{2} + \sin^{2} (\frac{π}{9})}

Commented by mathdanisur last updated on 15/Jul/21

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