Answer
The equivalent trigonometric form of $-8 - 15i$ is $17cis241.93^\circ$ or $17(cos241.93^\circ + isin241.93^\circ)$.
Work Step by Step
For $-8 - 15i$, the absolute value is $\sqrt{(-8)^2 + (-15)^2} = 17$ and $\theta = arctan(\frac{-15}{-8}) = 241.93^\circ$, since $-8 - 15i$ is in the 3rd quadrant.
Therefore, the equivalent trigonometric form of $-8 - 15i$ is $17cis241.93^\circ$ or $17(cos241.93^\circ + isin241.93^\circ)$.
