[tex]\\|AC|^2=7^2-4^2=49-16=33 \\AC|=\sqrt{33} \\sin\alpha=\frac{\sqrt33}{7} \\cos\alpha=\frac47 \\tg\alpha=\frac{\sqrt33}{4} \\ctg\alpha=\frac{4\sqrt33}{33}[/tex]
a = 4cm
b = ?
c = 7cm
a² + b² = c²
4² + b² = 7²
b² = 49 - 16
b² = 33
b = √33
sina = √33 / 7
cosa = 4 / 7
tga = √33 4
ctga = 4 / √33 = 4√33 / 33