We are asked to determine the endpoints of 5pi/4. The problem can be exemplified in the following diagram:
The x-coordinate of the endpoint is given by:

Solving the operations:
![x=-\frac{\sqrt[]{2}}{2}](https://img.qammunity.org/2023/formulas/mathematics/college/otgf8nov0k3pdxkorngpds777ozq068bby.png)
The y-coordinate of the endpoint is:

Solving the operation:
![y=-\frac{\sqrt[]{2}}{2}](https://img.qammunity.org/2023/formulas/mathematics/college/fpqjbwk6vvfuy3w6uhogl64ixj33eryjkj.png)
Therefore, the endpoint is:
![(-\frac{\sqrt[]{2}}{2},-\frac{\sqrt[]{2}}{2})](https://img.qammunity.org/2023/formulas/mathematics/college/ts1o5g3648xhmue4ksdfx3qhflohy133ko.png)