3.求lim(1+3sinx) CSC x x→>0 解原式=lim(1+3sinx)3m I lim(1+3sin x)sinx=Oy 03. 求 csc 0 lim(1 3sin ) . x x x → + 解 3 1 3sin 0 lim (1 3sin ) x x x →   = +     3 = e . 原式 3 1 3sin 0 lim(1 3sin ) x x x →   = +    