Question

De acordo com as relações fundamentais trigonométricas responda:
a) Seno= - 1/2
Cosseno=?
Tangente=?​

Answer 1

O quadrante a qual x pertence não foi informado portanto vou admitir que pertença ao 4º quadrante

$\mathsf{sen^2(x)+cos^2(x)=1}\\\mathsf{(-\dfrac{1}{2})^2+cos^2(x)=1}\\\mathsf{ \dfrac{1}{4}+cos^{2}(x)=1}\\\mathsf{cos^2(x)=1-\dfrac{1}{4}}$

$\mathsf{cos^2(x)=\dfrac{4-1}{4}}\\\mathsf{cos^2(x)=\dfrac{3}{4}}\\\mathsf{cos(x)=\pm\sqrt{\dfrac{3}{4}}}$

$\boxed{\boxed{\boxed{\boxed{\mathsf{cos(x)=\dfrac{\sqrt{3}}{2}}}}}}$

$\mathsf{tg(x)=\dfrac{sen(x)}{cos(x)}}\\\mathsf{tg(x)=\dfrac{-\frac{1}{2}}{\frac{\sqrt{3}}{2}}}\\\mathsf{tg(x)=-\dfrac{1}{2}.\dfrac{2}{\sqrt{3}}}$

$\mathsf{tg(x)=-\dfrac{1}{\sqrt{3}}}\to\large\boxed{\boxed{\boxed{\boxed{\mathsf{tg(x)=-\dfrac{\sqrt{3}}{2}}}}}}$