Lesson 4: 2.4 Complex Numbers
Duration of Days: 2
Lesson Objective
Use the imaginary unit to write complex numbers
Add, subtract, and multiply complex numbers
Use the complex conjugates to write the quotient of two complex numbers in standard form.
Find complex solutions of quadratic equations
How do you perform operations with complex numbers?
complex number, imaginary unit
HSN-CN.A.1: Know there is a complex number i such that i^2 = -1, and every complex number has the form a + bi with a and b real.
HSN-CN.A.2: Use the relation i^2 = -1 and the commutative, associative, and distributive properties to add, subtract, and multiply complex numbers.
HSN-CN.B.5: Represent complex numbers and their operations on the complex plane.
Use Khan Academy
The use of imaginary numbers will allow students to find solutions of quadratic and other polynomial equations that are not in the set of real numbers.
Complex numbers are used to model numerous aspects of the natural world such as the impedance of an electrical circuit.
Some students might not realized that pure imaginary numbers have conjugates too, such as 8i is -8i.
Have students summarize the major points of the essential question. More advanced groups should be able to come up with multiple concepts from this section.
Use common assessments
PreCalc with Limits