求极限n→∞lim[(2²ⁿ-8)/(4ⁿ+3ⁿ)]
原式=n→∞lim[(4ⁿ-8)/(4ⁿ+3ⁿ)=n→∞lim{(1-8/4ⁿ)/[1+(3/4)ⁿ]}=1
因为n→∞时,8/4ⁿ→0；(3/4)ⁿ→0.