In this Section we introduce De Moivre’s theorem and examine some of its consequences. We shall see that one of its uses is in obtaining relationships between trigonometric functions of multiple angles (like sin 3 x , cos 7 x ) and powers of trigonometric functions (like sin 2 x , cos 4 x ). Another important use of De Moivre’s theorem is in obtaining complex roots of polynomial equations. In this application we re-examine our definition of the argument arg ( z ) of a complex number.


Learning Outcomes

View these resources in original pdf format