### Instruction: Convert $e^{11 \pi i/2}$ to rectangular form.### Response: To convert this into rectangular form, we need to find the real and imaginary components.
The real component is $\cos(11\pi/2)$ and the imaginary component is $\sin(11\pi/2)$.
$\cos(11\pi/2)$ is equal to $0$ and $\sin(11\pi/2)$ is equal to $-1$.