trigonometry - Proving that $\tan \theta=\cot(90^\circ-\theta)$ when $\theta>90^\circ$ - Mathematics Stack Exchange
Trigonometric Ratios of Acute Angles. Rt △ ABC ∠ ACB=90° To ∠ BAC : Opposite: a=BC Hypotenuse: h=AB Adjacent: b=AC NameAbbreviationExpressionSinesina/h. - ppt download