Answer
$\left( -1.857,-3.543 \right)$
Work Step by Step
To determine rectangular coordinate from the polar coordinate, follow the following steps:
Step I: Press 2nd and then press APPS key to open Angle Menu.
Step II: Press 7.
Step III: Enter the point $\left( r,\theta \right)$ and press enter to display x in the $\left( x,y \right)$ rectangular form of the point.
Thus, $x=-1.857$
Step IV: Follow Step I and Step II and then press 8.
Step V: Enter the point $\left( r,\theta \right)$ and press enter to display y in the $\left( x,y \right)$ rectangular form of the point.
Thus, $y=-3.543$
Hence, the rectangular coordinate of $\left( -4,1.088 \right)$ is $\left( -1.857,-3.543 \right)$.