Question

Calcule o valor de Sen7 π/3
Calcule o valor de Cos 1380°

*cálculos por favor.​

Answer 1

$\boxed{\begin{array}{l}\sf\dfrac{7\pi} {3}=\dfrac{6\pi}{3}+\dfrac{\pi}{3}=2\pi+\dfrac{\pi}{3}\\\sf sen\bigg(\dfrac{7\pi}{3}\bigg)=sen\bigg(\dfrac{\pi} {3}\bigg) =\dfrac{\sqrt{3}}{2}\\\sf 1380^\circ=3\cdot360^\circ+300^\circ\\\sf cos(1380^\circ)=cos(300^\circ)=cos(60^\circ)=\dfrac{1}{2}\end{array}}$