{xf(a)+af(x)}/x,求x趋近于a的极限,
问题描述:
{xf(a)+af(x)}/x,求x趋近于a的极限,
答
lim x->a {xf(a)+af(x)}/x
= lim x->a xf(a)/x + lim x->a af(x)/x
= lim x->a f(a) + lim x->a f(x)*a/x
= f(a) + lim x->a f(x) * lim x->a a/x
=f(a) + f(a) * 1
=2f(a)