Disclaimer: The material in the videos below comes mainly from outside City Tech. The presentation in these videos may differ from the one given in your class. Please consult with your instructor to confirm whether a particular approach is acceptable in your class.
- $\rhd$ Plotting numbers on the complex plane (1:13) Plotting the numbers: $-2+2i$, $5+2i$, $1+5i$ and $4-4i$.
- $\rhd$ Absolute value of a complex numbers (3:32) Finding the absolute value of $z=3-4i$
- $\rhd$ Absolute value & angle of complex numbers (13:03) Finding the absolute value and the argument of $\dfrac{\sqrt{3}}{2}+\dfrac{1}{2}i$.
- $\rhd$ Polar & rectangular forms of complex numbers (12:15) Finding the polar form of $z=-3+2i$.
- * Practice: Polar & rectangular forms of complex numbers. (4 problems)
- $\rhd$ Multiply complex numbers in polar form (4:43) Multiply: $2(\cos 120^\circ+i\sin 120^\circ)\cdot 4(\cos 90^\circ+i\sin 90^\circ)$
- $\rhd$ Multiplying and dividing complex numbers in polar form (3:26) Divide: $\dfrac{6(\cos(60^{\circ})+i \sin(60^{\circ}))}{3(\cos(90^{\circ})+i \sin(90^{\circ}))}$. Multiply: $[2(\cos(45^{\circ})+i \sin(45^{\circ}))]\cdot [5(\cos(30^{\circ})+i \sin(30^{\circ}))]$.
