令 t=- lim(+)=lim(1-)-=lim(xf- x→-00 t→+α =lim(1+)-(1+,)=e t→+0 im(1+-)=e 令【=,Ⅲim(1+x)=lim(1+)=e x→0 lim(1+x)=e x→0令 t = −x, t t x x x t − →−  →+   + = − ) 1 ) lim(1 1 lim (1 t t t ) 1 1 lim (1 − = + →+ ) 1 1 ) (1 1 1 lim(1 1 − + − = + − →+  t t t t = e. e x x x  + = → ) 1 lim(1 , 1 x 令 t = t t x x t x ) 1 lim(1 ) lim(1 1 0 + = + → → = e. x e x x + = → 1 0 lim(1 )