Question

Z1=2(cos30°+i sin30°) Z2=1/2(cos10°+i sin10°) Z1×z2; z1÷z2; z1^2 Help please

Answer 1

$z_{1}z_{2}=cos40к+isin40к$

$\frac{z_{1}}{z_{2}}=4(cos20к+isin20к)$

$z_{1} ^2=4(cos60к+isin60к)$

Пошаговое объяснение:

$z_{1}=2(cos30к+isin30к)=2e^{\frac{i\pi}{6}$

$z_{2}=\frac{1}{2} (cos10к+isin10к)=\frac{1}{2} e^{\frac{i\pi}{18}$

$z_{1}z_{2}=2e^{\frac{i\pi}{6}}\frac{1}{2} e^{\frac{i\pi}{18}}=e^{\frac{i\pi}{6}+\frac{i\pi}{18}}=e^{\frac{2i\pi}{9}}=cos40к+isin40к$

$\frac{z_{1}}{z_{2}}=\frac{2e^{\frac{i\pi}{6}}}{\frac{1}{2} e^{\frac{i\pi}{18}}} =4e^{\frac{i\pi}{6}-\frac{i\pi}{18}}=4e^{\frac{i\pi}{9}}=4(cos20к+isin20к)$

$z_{1} ^2=(2e^{\frac{i\pi}{6}})^2=4e^{\frac{i\pi}{3}}=4(cos60к+isin60к)$