Answer
The equivalent trigonometric form of $3 - 4i$ is $5cis306.87^\circ$ or $5(cos306.87^\circ + isin306.87^\circ)$.
Work Step by Step
For $3 - 4i$, the absolute value is $\sqrt{3^2 + (-4)^2} = 5$ and $\theta = arctan(\frac{-4}{3}) = 306.87^\circ$, since $3 - 4i$ is in the 4th quadrant.
Therefore, the equivalent trigonometric form of $3 - 4i$ is $5cis306.87^\circ$ or $5(cos306.87^\circ + isin306.87^\circ)$.
