A:an art much a
B:much an art a
C:as an art much a
D:as much an art a
如图,椭圆E:x2a2+y2b2=1(a>b>0)的离心率是22,过点P(0,1)的动直线l与椭圆相交于A,B两点,当直线l平行与x轴时,直线l被椭圆E截得的线段长为22.
96÷16=____
240÷60=____
200÷8=____
240÷24=____
已知:如图,在四边形ABCD中,E,F分别是AB,CD的中点,且EF=12(AD+BC).求证:AD∥BC.