Question

跪求：已知函数f(x)=ax^3+bx+2,且f(2)=8,则f(-2)=?

Answer 1

f(2)=8a+2b+2=8,
f(-2)=-8a-2b+2
=-(8a+2b+2)+4=-8+4=-4

Answer 2

答案是-6
设G(x)=f(x)-2=ax^3-bx=6;
G(x)是奇函数所以-G(x)=G(-x);
G(2)=f(2)-2=8-2=6;
G(-2)=-G(2)=-6;

Answer 3

f(2)=8a+2b+2=8,
f(-2)=-8a-2b+2
=-(8a+2b+2)+4=-8+4=-4