Найдите tga если cosa корень 17/17

[latex]cos a = frac{sqrt{17}}{17}\ \ cos^2 a = frac{17}{17^2} = frac{1}{17}\ \ an^2 a = frac{sin^2 a}{cos^2 a} = frac{1-cos^2 a}{cos^2 a}= \ =frac{1 - 1/17}{1/17}=frac{16/17}{1/17}=16\ \ an a = pm sqrt{16} = pm 4[/latex]