Question

упростить tga-tgb/ctga-ctgb

Answer 1

$frac{tga-tgb}{ctga-ctgb}= frac{frac{sina}{cosa}-frac{sinb}{cosb}}{frac{cosa}{sina}-frac{cosb}{sinb}}=frac{frac{sinacosb-cosasinb}{cosacosb}}{frac{cosasinb-sinacosb}{sinasinb}}=-frac{(sinacosb-cosasinb)sinasinb}{cosacosb*(sinacosb-cosasinb)}= \ =- frac{sinasinb}{cosacosb}=-tga*tgb$