Question

Alguém ?????/?

Imagem em Anexo:

Gabarito, a) -0,4. , b) 0,4. ,c) -0,4.

Answer 1

As propriedades abaixo valem para qualquer arco $\alpha$, onde $\alpha \neq 90^{\circ}+k\cdot 180^{\circ},\;\;k \in \mathbb{Z}$:

$\mathrm{tg}\left(-\alpha+k\cdot 180^{\circ} \right )=-\mathrm{tg\,}\alpha\\ \\ \mathrm{tg}\left(\alpha+k\cdot 180^{\circ} \right )=\mathrm{tg\,}\alpha$


$\mathrm{tg\,}22^{\circ}=0,4$


a) $\mathrm{tg\,}158^{\circ}$

$\mathrm{tg\,}158^{\circ}=\mathrm{tg}\left(-22^{\circ}+180^{\circ} \right )\\ \\ \mathrm{tg\,}158^{\circ}=-\mathrm{tg\,}22^{\circ}\\ \\ \mathrm{tg\,}158^{\circ}=-0,4$


b) $\mathrm{tg\,}202^{\circ}$

$\mathrm{tg\,}202^{\circ}=\mathrm{tg}\left(22^{\circ}+180^{\circ} \right )\\ \\ \mathrm{tg\,}202^{\circ}=\mathrm{tg\,}22^{\circ}\\ \\ \mathrm{tg\,}202^{\circ}=0,4$


c) $\mathrm{tg\,}338^{\circ}$

$\mathrm{tg\,}338^{\circ}=\mathrm{tg}\left(-22^{\circ}+360^{\circ} \right )\\ \\ \mathrm{tg\,}338^{\circ}=\mathrm{tg}\left(-22^{\circ}+2\cdot 180^{\circ} \right )\\ \\ \mathrm{tg\,}338^{\circ}=-\mathrm{tg\,}22^{\circ}\\ \\ \mathrm{tg\,}338^{\circ}=-0,4$