Exercício sobre seno

Calcule:

sen 300°

sen 330°

sen $\,5\pi\,$

sen$\,-\frac{\,\pi\;}{\;4\;}\,$

$\,\dfrac{sen\,\frac{\,\pi\,}{\,2\,}\;-\;sen\,\frac{\,\pi\,}{\,3\,}}{sen\,\frac{\,\pi\,}{\,6\,}}\,$

$\,\dfrac{sen\,\frac{\,\pi\,}{\,4\,}\;-\;sen\,\frac{\,4\pi\,}{\,3\,}}{sen^2\,\frac{\,5\pi\,}{\,6\,}}\,$

resposta:

$\,\frac{-\sqrt{3}}{2}\,$

-1/2

$\,\frac{-\sqrt{2}}{2}\,$

$\,2 - \sqrt{3}\,$

$\,-\sqrt{\,6\;}\,$