ANSWER
![- (\pi)/(4)](https://img.qammunity.org/2020/formulas/mathematics/high-school/7a92y0b26jinh94pong7o3nujkmjr9jcc8.png)
Step-by-step explanation
The given function is,
![f(t) = 2 \csc(t + (\pi)/(4) ) - 1](https://img.qammunity.org/2020/formulas/mathematics/high-school/tfza87njjh3gflc4w0wbd8wi8t1y3utl5c.png)
This function has a period of
![2\pi](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ia5d2u08w0ivg4tfm7kmao3az9h7oxlde3.png)
just as the parent function
![f(t) = \csc(t )](https://img.qammunity.org/2020/formulas/mathematics/high-school/ey4jotbw92aae5p57ico3qwyzfzg7jxyxi.png)
A sample period of this parent function is
![[ 0 , 2\pi]](https://img.qammunity.org/2020/formulas/mathematics/high-school/iss1alw9pgar6p6mx0r2nioxbxn4gk61y1.png)
Which begins at zero.
For the transformed function,
![f(t) = 2 \csc(t + (\pi)/(4) ) - 1](https://img.qammunity.org/2020/formulas/mathematics/high-school/tfza87njjh3gflc4w0wbd8wi8t1y3utl5c.png)
There has been a horizontal shift of
![(\pi)/(4)](https://img.qammunity.org/2020/formulas/mathematics/high-school/wlxcvibky3yxk3si4j8tqg9zy8pdi6sjhd.png)
to the left.
The transformed function will have a sample period,
![[ - (\pi)/(4) , (7\pi)/(4) ]](https://img.qammunity.org/2020/formulas/mathematics/high-school/c6ublastjh83u2ga8sjzdanjdu0yq80igq.png)
Therefore a sample period begins at
![- (\pi)/(4)](https://img.qammunity.org/2020/formulas/mathematics/high-school/7a92y0b26jinh94pong7o3nujkmjr9jcc8.png)