用反证法易得
假设lim(x趋x零)[f(x)+g(x)]=B,
则由g(x)=f(x)+g(x)] - f(x)得lim(x趋x零)g(x)=B-A,与条件矛盾.
若lim(x趋近于x零f(x)=A,lim(x趋x零）g(x)=无穷大,x趋于x0 ,证明[f(x)+g(x)]不存在.
用反证法易得
假设lim(x趋x零)[f(x)+g(x)]=B,
则由g(x)=f(x)+g(x)] - f(x)得lim(x趋x零)g(x)=B-A,与条件矛盾.