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Kąt alfa jest ostry. Oblicz cos alfa
Sin alfa = 9/41 = 0.21951219512195
Oblicz tan alfa


Odpowiedź :

[tex]sin^2\alpha+cos^2\alpha=1\\\\(\frac{9}{41})^2+cos^2\alpha=1\\\\\frac{81}{1681}+cos^2\alpha=1\\\\cos^2\alpha=1-\frac{81}{1681}\\\\cos\alpha=\frac{1600}{1681}\\\\cos\alpha=\sqrt{\frac{1600}{1681}}\\\\cos\alpha=\frac{40}{41}[/tex]