In trigonometric form : 0.632[cos(−71.565)+isin(−71.565)]
Explanation:
−4i+2i+7=(−4i+2)(i−7)(i+7)(i−7)=−4⋅i2−14+30⋅ii2−72=(−150)⋅(−10+30i)=0.2−0.6i. Let Z=0.2−0.6i Modulas Z= √0.22+(−0.6)2=.632 Argument Z θ=tan−1(−0.60.2)=tan−1(−3)=−71.5650 Hence Z expressed in trigonometric form: 0.632[cos(−71.565)+isin(−71.565)][Ans]