(lntan7x)'=7(1/tan7x)(tan(7x)^2+1)(lntan2x)'=2(1/tan2x)(tan(2x)^2+1)(lntan7x)'/(lntan2x)'=(7/2)*(tan2x/tan7x)*((tan(7x)^2+1)/(tan(2x)^2+1))(tan7x)'=7(tan(7x)^2+1)(tan2x)'=2(tan(2x)^2+1)limlntan7x/lntan2x=lim(lntan7x)'/(lntan2x)'=(7/2)*(limtan2x/tan7x)*lim(tan(7x)^2+1)/(tan(2x)^2+1) =(14/4)(lim(tan7x)'/(tan2x)')*1 =(14/4)(lim(tan(7x)^2+1)/(tan(2x)^2+1))*1 =(14/4)*1*1 =14/4
匿名回答于2024-06-06 10:06:17
