Sinus cosinus ♦ Cercle trigonométrique

$\color{red}{\textbf{a. }} \cos\left(\dfrac \pi 2\right)$ $\color{red}{\textbf{b. }} \sin\left(\dfrac \pi 2\right)$ $\color{red}{\textbf{c. }} \cos\left(0\right)$ $\color{red}{\textbf{d. }} \sin (0)$ $\color{red}{\textbf{e. }} \cos\left(\dfrac \pi3 \right)$ $\color{red}{\textbf{f. }} \sin\left(\dfrac \pi 4 \right)$ $\color{red}{\textbf{g. }} \sin\left(\dfrac \pi 6 \right)$ $\color{red}{\textbf{h. }} \cos\left(\pi \right)$ $\color{red}{\textbf{i. }} \sin\left(\pi \right)$ $\color{red}{\textbf{j. }} \cos\left(2\pi \right)$ $\color{red}{\textbf{k. }} \sin\left(2\pi \right)$

$\color{red}{\textbf{a. }} \sin\!\left(\dfrac {7\pi} 6\right)$ $\color{red}{\textbf{b. }} \cos\!\left(\dfrac {5\pi} 6\right)$ $\color{red}{\textbf{c. }} \cos\!\left(\dfrac{2\pi}3\right)$ $\color{red}{\textbf{d. }} \sin\!\left(\!-\dfrac \pi4 \right)$ $\color{red}{\textbf{e. }} \cos\!\left(\!-\dfrac {3\pi} 4 \right)$