(Ⅰ)求a,b的值;
(Ⅱ)求函数f(x)的极值.
His cousin hardly has vegetables these days, __________?
I was ____ tired ____ I went to sleep early.
在金属导体中,若10s内通过横截面的电荷量为10C,则导体中的电流为I=____A.某电解槽横截面积为0.5m2,若10s内沿相反方向通过横截面的正负离子的电荷量均为10C,则电解液中的电流为I=____A.