Complex Numbers And Quadratic Equations question 835

Question: Real part of $ {e^{{e^{i\theta }}}} $ is [RPET 1995]

Options:

A) $ {e^{\cos \theta }}[\cos (\sin \theta )] $

B) $ {e^{\cos \theta }}[\cos (\cos \theta )] $

C) $ {e^{\sin \theta }}[\sin (\cos \theta )] $

D) $ {e^{\sin \theta }}[\sin (\sin \theta )] $

Show Answer

Answer:

Correct Answer: A

Solution:

$ {e^{{e^{i\theta }}={e^{\cos \theta +i\sin \theta }}={e^{\cos \theta }}[{e^{i\sin \theta }}]}} $ $ ={e^{\cos \theta }}[\cos (\sin \theta )+i\sin (\sin \theta )] $ \ Real part of $ {e^{{e^{i\theta }}}} $ is $ {e^{\cos \theta }}[\cos (\sin \theta )] $