matma

sin, cos, tg etc.

1.

$si{n}^2\alpha +co{s}^2\alpha =1$ $si{n}^2\alpha +\frac{12}{13}=1$ $si{n}^2=1-\frac{144}{169}$ $si{n}^2=\frac{25}{169}$ $si{n}^2=513$ $\frac{sin}{cos}=\frac{5/13}{12}13=513\ast \frac{13}{12}=\frac{5}{12}$

2.

$tg=\frac{\sqrt{2}}{2}$ $tg\alpha =\frac{a}{b}$ ${\sqrt{2}}^2+2^2=c^2$ $c=\sqrt{6}$

3.

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$si{n}^2\alpha +co{s}^2\alpha =1$ $cos\alpha =\frac{sin\alpha }{cos\alpha }$

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4.

$cos\alpha =\frac{\sqrt{5}}{5}$ | $ctg\alpha =\sqrt{2}$

$sin\alpha =?$