Question

AJUDA URGENTE !!!!!!!!​

Answer 1

Resposta:

Letra D)-3/5

Explicação passo-a-passo:

$sen^{2}x+cos^{2}x=1 \\tg x=\frac{senx}{cosx}\\\\\frac{1}{2}=\frac{senx}{cosx}\\\\2senx=cosx\\sen^{2}x+(2senx)^{2}=1\\5sen^{2}x=1\\sen^{2}x=\frac{1}{5}\\\frac{1}{5} +cos^{2}x=1\\cos^{2}x=1-\frac{1}{5}\\cos^{2}x=\frac{4}{5}\\\\E=sen^{2}x-cos^{2}x\\E=\frac{1}{5}-\frac{4}{5}\\E=-\frac{3}{5}$