a\color{red}{a} b\color{red}{b} c\color{red}{c} β\color{blue}{\beta} α\color{blue}{\alpha}
α+β=90° \alpha + \beta = 90° a2+b2=c2 a^2 + b^2 = c^2 cos(α)=sin(β)=bc {\cos(\alpha)} = {\sin(\beta)} = \frac{b}{c} cos(β)=sin(α)=ac {\cos(\beta)} = {\sin(\alpha)} = \frac{a}{c} tan(α)=sin(α)cos(α)=cot(β)=cos(β)sin(β)=ab {\tan(\alpha)} = \frac{\sin(\alpha)}{\cos(\alpha)} = {\cot(\beta)} = \frac{\cos(\beta)}{\sin(\beta)} = \frac{a}{b} tan(β)=sin(β)cos(β)=cot(α)=cos(α)sin(α)=ba {\tan(\beta)} = \frac{\sin(\beta)}{\cos(\beta)} = {\cot(\alpha)} = \frac{\cos(\alpha)}{\sin(\alpha)} = \frac{b}{a}