e^x=1+1/1!x+1/2!x²+.+1/n!x^n+.
y=e^x=e* (e^(x-1))
因为e^x=1+1/1!x+1/2!x²+.+1/n!x^n+.
所以
把x换成x-1,得
y=e^x=e*e^(x-1)=e*(1+1/1!(x-1)+1/2!(x-1)²+.+1/n!(x-1)^n+.)
x∈R