Răspunsuri

2014-02-26T21:04:19+02:00
Folosind formula de inmultire a doua numere complexe scrise sub forma trigonometrica, obtinem:
...=\cos(\dfrac{\pi}{4}+\dfrac{3\pi}{4})+i\sin(\dfrac{\pi}{4}+\dfrac{3\pi}{4})=\cos\pi+i\sin\pi
deci argumentul este \pi, iar modulul este \cos^2\pi+\sin^2\pi=1.


Formula de care vorbeam mai sus:
z_1=r_1(\cos x_1+i\sin x_1);\ z_2=r_2(\cos x_2+i\sin x_2)\Rightarrow\Rightarrow z_1\cdot z_2=r_1\cdot r_2[\cos(x_1+x_2)+i\sin(x_1+x_2)]