设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f'(t)

来源:学生作业帮助网 编辑:六六作业网 时间:2024/07/05 21:06:40
设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f''(t)设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f''(t)设f(t)=lim(x→∞)t(1+2/x)^(x-t),求

设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f'(t)
设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f'(t)

设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f'(t)
设f(t)=lim(x→∞)t(1+2/x)^(x-t),求f'(t)
解;∵t(1+2/x)^(x-t)=t[(1+2/x)^(x/2)]²[(1+2/x)^(-t)]
∴f(t)=x→∞limt(1+2/x)^(x-t)=x→∞limt[(1+2/x)^(x/2)]²[(1+2/x)^(-t)]=e²t
故f′(t)=e².