函数f(x)在x=a处的泰勒展开式(幂级数展开法)为:f(x)=f(a)+[f'(a)/1!]*(x-a)+[f''(a)/2!*(x-a)^2]+...[f^(n)(a)/n!]*(x-a)^n+...f(x)=2^x,f(0)=1f'(x)=2^x*ln2,f'(0)=ln2f''(x)=2^x*(ln2)^2,f''(0)=(ln2)^2...f^(n)(x...