Cho tan a = 7/8 .Tính tan ( − a ) .4/39Cho\(\tan a = \frac{7}{8}\).Tính\[\tan ( - a)\].\(\frac{7}{8}\).\( - \frac{7}{8}\).\(\frac{{15}}{{16}}\).\( - \frac{{15}}{{16}}\).Giải thíchChọn B Ta có: \(\tan (\pi - a) = - \tan a = - \frac{7}{8}\).