T&T6: Ex3.9&10 De Moivre's Theorem

Write the expression in the standard form a + bi.
[4(cos40 +isin40)]³

• -32 + 32√3i
• 32 - 32√3i
• 16√i +16
• 4 + 4√i

Covert to polar form then solve using DeMoivre's Theorem

• 72 - 72√3i

• - 72√3 + 72i

• - 72√2 + 72√2i

• -72 + 72√3i

Find the indicated power using DeMoivre's Theorem 

• 256
• 4096i
• 4096
• -4096

Find 
(3 + 3√3 i )⁴ 
using De Moivre's Theorem and express your answer in rectangular form.

• -648 - 648 √3 i
• -654 - 654 √3 i
• -1962 - 1962 √3 i
• 648 i

Which of the following is NOT a root of the equation below?

 $z^3=8$  

• √3 + i

• 2i

• -√3 + i

• -2i