a)
a=4
c=8,2
b=\sqrt{c^2-a^2}=\sqrt{8,2^2-4^2}=\sqrt{67,24-16}=\sqrt{51,24}\approx 7,1582
sin\alpha=\frac{a}{c}=\frac{4}{8,2}=\frac{40}{82}\approx0,4878
cos\beta=\frac{a}{c}=sin\alpha=0,4878
b)
a=2
b=4
tg\alpha=\frac{a}{b}=\frac{2}{4}=\frac{1}{2}
tg\beta=\frac{b}{a}=\frac{4}{2}=2
c)
b=4,2
c=5
cos\alpha=\frac{b}{c}=\frac{4,2}{5}=0,84
sin\beta=\frac{b}{c}=\frac{4,2}{5}=0,84
d)
b = 4
c = 5
a=\sqrt{c^2-b^2}=\sqrt{5^2-4^2}=\sqrt{25-16}=\sqrt9=3
a=3
sin\alpha=\frac{a}{c}=\frac{3}{5}
cos\beta=\frac{a}{c}=\frac{3}{5}