Chapter 8, Problem 50RE

To determine

To graph: The function $f\left(t\right)=\sin t+\cos t$ for $-2\pi \le t\le 2\pi$, by using the points $t$ between $-2\pi$ to $2\pi$ such that $f^{\prime }\left(t\right)=0$, concavity of the function $f\left(t\right)$ and the inflection points of the function $f\left(t\right)$.