A、<img src="http://wximg.233.com/attached/image/20150822/20150822174009_4774.png" height="28" width="27" />
B、<img src="http://wximg.233.com/attached/image/20150822/20150822174014_3996.png" height="28" width="51" />
C、1/3
D、<img src="http://wximg.233.com/attached/image/20150822/20150822174022_2284.png" height="28" width="40" />
高等数学二