Question

Reduza para o primeiro quadrante e determine :​

Answer 1

$\mathtt{a)}~\mathsf{sen(120^{\circ})=sen(180^{\circ}-120^{\circ}) =sen(60^{\circ}=\dfrac{\sqrt{3}}{2}}\\\mathtt{b)}~\mathsf{sen(135^{\circ})=sen(180^{\circ}-135^{\circ})=sen(45^{\circ})=\dfrac{\sqrt{2}}{2}}\\\mathtt{c)}~\mathsf{sen(150^{\circ})=sen(180^{\circ}-150^{\circ})=sen(30^{\circ})=\dfrac{1}{2}}\\\mathtt{d)}~\mathsf{sen(225^{\circ})=-sen45^{\circ}=-\dfrac{\sqrt{2}}{2}}\\\mathtt{e)}~\mathsf{sen(300^{\circ}=-sen(60^{\circ})=-\dfrac{\sqrt{3}}{2}}\\\mathtt{f)}~\mathsf{cos(120^{\circ})=-cos(60^{\circ})=-\dfrac{1}{2}}\\\mathtt{g)}\mathsf{cos(135^{\circ})=-cos(45^{\circ})=-\dfrac{\sqrt{2}}{2}}\\\mathtt{h)}~\mathsf{cos(150^{\circ})=-cos(30^{\circ})=-\dfrac{\sqrt{3}}{2}}\\\mathtt{i)}~\mathsf{cos(225^{\circ}) =-cos(45^{\circ})=-\dfrac{\sqrt{2}}{2}}\\\mathtt{j)}~\mathsf{cos(300^{\circ})=cos(60^{\circ})=\dfrac{1}{2}}$