(I)解:因为图象关于原点对称,所以f(x)为奇函数,所以b=0,d=0
所以f(x)=ax3+cx,因此f'(x)=3ax2+c
由题意得f1=
—We cross the road at ____ ____.
1÷ 32 × 23 =____
8 12 +1 12 ×0=____
45+90÷45+90=____
8×125%=____
2+ 12 =____
7.1+ 25 =____
( 14 ﹣ 16 )×24=____
4﹣1 34 =____
14 ﹣ 15 =____
55+45=____