Wednesday, 25 December 2019

trigonometry - Modulus of tangent of complex number



I need to find real, imaginary parts of tan(x+yi) and the modulus of it. I have:
Re(tan(x+yi))=sin2xcos2x+cosh2x
and
Im(tan(x+yi))=sinh2ycos2x+cosh2x



I know that |Z|=Re2+Im2. But when I calculate with the results I've got, I don't get the actual answer on the book, which is cosh2ycos2xcosh2y+cos2x


Answer




You can observe that
sin22x+sinh22y=1cos22x+cosh22y1=cosh22ycos22x=(cosh2y+cos2x)(cosh2ycos2x)


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