As middle school students, we _______ be afraid of difficulties if we want to make our dreams come true.
A:must
B:shouldn't
C:need
(I)求椭圆C的方程;
(II)设M(x1,y1),N(x2,y2)(x1≠x2)为椭圆上的两点,且满足 OM→ • ON→ = a2x1x2+b2y1y2a2+b2 ,求证:△MON的面积为定值,并求出这个定值.
已知函数f(x)=lnx+2x,则不等式f(x2﹣3)<2的解集为____ .