In Mathville, the time for the sunrise for any day during the year can be modeled by the formula;
$$t=1.15\sin\bigg[\frac{2\pi}{365}(d-74)\bigg]+7$$
where $t$ is the time in hours after midnight and $d$ is the number of days in the year (excluding leap year).
What are the earliest and latest sunrise times (in Hr:Min format) during year 1 ?
My approach:
Should I be using the derivative to find the least and the greatest value of $t$, then finding the critical points, and then the second derivative?