Вычислите значение тригонометрических функций если 1) sin = - 5/13 и 3/2<< ? 2) cos = -...

Question

Вычислите значение тригонометрических функций если
1) sin = - 5/13 и 3/2<<img src="https://tex.z-dn.net/?f=+%5Calpha+" id="TexFormula3" title=" \alpha " alt=" \alpha " align="absmiddle" class="latex-formula"><<img src="https://tex.z-dn.net/?f=+%5Cpi+" id="TexFormula4" title=" \pi " alt=" \pi " align="absmiddle" class="latex-formula"> ?
2) cos = - 8/18 и /2<<img src="https://tex.z-dn.net/?f=+%5Calpha+" id="TexFormula7" title=" \alpha " alt=" \alpha " align="absmiddle" class="latex-formula"><<img src="https://tex.z-dn.net/?f=+%5Cpi+" id="TexFormula8" title=" \pi " alt=" \pi " align="absmiddle" class="latex-formula"> ?
3) tg =8/15 и <<img src="https://tex.z-dn.net/?f=+%5Calpha+" id="TexFormula11" title=" \alpha " alt=" \alpha " align="absmiddle" class="latex-formula"><3<img src="https://tex.z-dn.net/?f=+%5Cpi+" id="TexFormula12" title=" \pi " alt=" \pi " align="absmiddle" class="latex-formula">/2 ?
Плиз хелп))!!!
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Answer 1

1)cosa=√1-sin²a=√1-25/169=√144/169=12/13
tga=sina/cosa=-5/13^12/13=-5/12
ctga=1/tga=-12/5
2)sina=√1-cosa=√1-64/324=√260/324=2√65/18=√65/9
tga=√65/9:(-8/18)=-√65/4
ctga=-4/√65
3)1+tg²a=1/cos²a
cos²a=1:(1+tg²a)=1:(1+64/225)=1:289/225=225/289
cosa=-15/17
sina=√1-225/289=√264/17=2√66/17
ctga=15/8