∵f(x)=ax3 bx2 cx d(a≠0),
∴f′(x)=3ax2 2bx c,f''(x)=6ax 2b,
∵f″(x)=6a*(-
b
3a ) 2b=0,
∴Any cubic function is about the point (-
b
3a ,f(-
b
3a )) Symmetry, that is, ① is correct;
∵Any cubic function has a symmetry center, and the "inflection point" is the symmetry center,
∴There is a cubic function f′(x)=0 with a real solution x0, and the point (x0, f(x0)) is the symmetry center of y=f(x), that is, ② is correct;
Any cubic function has one and only one center of symmetry, so ③ is incorrect;
∵g′(x)=x2-x,g″(x)=2x-1,
Let g″(x)=0, we can get x=
1
2, ∴g(
1
2 )=-
1
2 ,
∴g(x)=
1
3 x3-
1
2 x2-
5
The center of symmetry of12 is (
1
2 ,-
1
2 ),
∴g(x) g(1-x)=-1,
∴g(
1
2013 ) g(
2
2013 ) … g(
2012
2013 )=-1*1006=-1006, so ④ is correct.
So the answer is: ①②④.
①From f(x)=2x 3 -3x 2 -24x 12, we get f ′ =6x 2 -6x-24,f ′′ (x)=12x-6.
From f ′′ (x)=12x-6=0, we get x=
1
2 . f(
1
2 )=2*(
1
2 ) 3 -3*(
1
2 ) 2 -24*
1
2 12=-
1
2 .
So the symmetry center coordinate of the function f(x)=2x 3 -3x 2 -24x 12 is (
1
2 ,-
1
2 ) .
So the answer is (
1
2 ,-
1
2 ) .
②Because the symmetry center coordinate of the function f(x)=2x 3 -3x 2 -24x 12 is (
1
2 ,-
1
2 ) .
So f(
1
2013 ) f(
2012
2013 )=f(
2
2013 ) f(
2011
2013 )=…=2f(
1
2 )=2*(-
1
2 ) =-1.
by f(
2013
2013 )=f(1)=-13 .
So f(
1
2013 ) f(
2
2013 ) f(
3
2013 ) … f(
2012
2013 ) f(
2013
2013 ) =-1006-13=-1019.
So the answer is -1019.
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