Question

sabendo que sen x=1/2 e 90°<x<180°, calcule o valor de cos x. use a relação fundamental da trigonometria sen²x + cos²x=1​

Answer 1

Resposta:

1. begin{gathered}sen^{2}(x)+cos^{2}(x)=1 \\\\(\frac{1}{2} )^2+cos^{2}(x)=1\\\\(\frac{1}{4} )+cos^{2}(x)=1\\\\cos^{2}(x)=1-(\frac{1}{4})\\\\cos^{2}(x)=(\frac{3}{4})\\\\cos(x)=\sqrt{(\frac{3}{4})} \\\\cos(x)=\frac{\sqrt{3}}{2}}\\\\cos(30)=\frac{\sqrt{3}}{2}}\end{gathered}