6.5 Complex Numbers in Trigonometric FormObjectives:1) Convert complex numbers to trig form and vice versa2) Multiply/Divide complex numbers in trig form.

Standard: Math Analysis 2.0

Ex. 1) Given: –2+4i

a) Graph

b) |–2+4i|

c) Find the inclination

Ex. 2) Given r=5 and θ=142°, find the complex number a+bi at the same location.

a

b

r

θ

Trig Form Complex Form

Ex. 3) Write 6–6i in trig form.

Ex. 4) Write as a complex number.

Multiplying Complex Numbers in Trig FormStandard Form: (a+bi)(a+bi) = FOILTrig Form:

Ex. 5) Find z1z2.

Dividing Complex Numbers in Trig FormStandard Form: (a+bi)÷(a+bi) = multiply by conjugate

Trig Form:

Ex. 6) Find

Assignment:

#6 p. 478 #12-39 (mult. of 3), 47-57 (odd)