cos alfa = [tex]\frac{b}{c}[/tex]
cos alfa = [tex]\frac{2}{3}[/tex]
b = 2
c = 3
sin alfa = [tex]\frac{a}{c}[/tex]
sin alfa = [tex]\frac{a}{3}[/tex]
warto by było zrobić rysunek, a potem obliczyć z pitagorasa wartość a:
[tex]a^{2}[/tex] + [tex]b^{2}[/tex] = [tex]c^{2}[/tex]
[tex]a^{2} + 2^{2} = 3^{2} \\a^{2} = 9 - 4\\a^{2} = 5\\\a = \sqrt{5}[/tex]
a = [tex]\sqrt{5}[/tex]
b = 2
c = 3
sin alfa = [tex]\frac{\sqrt{5} }{3}[/tex]
tg alfa = [tex]\frac{a}{b}[/tex]
tg alfa = [tex]\frac{\sqrt{5} }{2}[/tex]
ctg alfa = [tex]\frac{b}{a}[/tex]
ctg alfa = [tex]\frac{2}{\sqrt{5} }[/tex] * [tex]\frac{\sqrt{5} }{\sqrt{5} }[/tex] = [tex]\frac{2\sqrt{5} }{5}[/tex]
