Saturday 28 May 2016

multivariable calculus - What are the real and imaginary parts of the complex function?




So, it is asked to find the real and imaginary parts of the specific complex function:



$f(z)=sin(z)+i(3z+2) $
So I use $z$ as $z=x+iy$



everything seemed clear till I met Mr. Sinus:



$u+iv= sin(x+iy)+i(3(x+iy)+2)$




and I don't really know how to seperate the imaginary and real parts of $sin(x+iy)$ argument.



Need hints...


Answer



Hint:



use addition formula: $\sin(x+iy)=\sin x \cos(iy)+\cos x \sin(iy)$ and remember that: $ \cos(iy)=\cosh(y)\;$ and $ \sin(iy)=i\sinh y$.


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