Complex Numbers Flashcards
1
Q
ways of expressing complex numbers
A
x + iy
re^iu
r(cosu+isinu)
2
Q
when multiplying complex numbers
A
Multiply their moduli and add the arguments
|z1z2| = |z1| |z2|
arg (z1z2) =arg (z1) + arg (z2)
3
Q
when dividing complex numbers
A
Divide their moduli and subtract their arguments
4
Q
z + 1/z
A
2cos u
5
Q
z- 1/z
A
2isin u
6
Q
z^n + 1/z^n
A
2 cos nu
7
Q
z^n - 1/z^n
A
2 isin nu
