lim(x->无穷)[(5x+1)/(5x-1)]^(4x)=?

问题描述:

lim(x->无穷)[(5x+1)/(5x-1)]^(4x)=?

这属於1^(无穷) 类形,主要都是用自然对数然後用洛必特法设 y= [5x+1)/(5x-1)]^(4x)lny = ln{[5x+1)/(5x-1)]^(4x)}lny = ln{[5x+1)/(5x-1)]^(4x)}= 4x ln{[5x+1)/(5x-1)}= 4 ln{[5x+1)/(5x-1)} / (1/x) 当 lim(x->无...