题目:f(x)=ax²+bx ,且 f(x-1)=f(x)+x-1恒成立,求f(x)
a(x-1)²+b(x-1)=ax²+bx+x-1
(1+2a)x=a-b+1
此式恒成立,1+2a=0 a-b+1=0
a=-1/2 b=1/2
f(x)=-1/2x²+1/2x
题目:f(x)=ax²+bx ,且 f(x-1)=f(x)+x-1恒成立,求f(x)
a(x-1)²+b(x-1)=ax²+bx+x-1
(1+2a)x=a-b+1
此式恒成立,1+2a=0 a-b+1=0
a=-1/2 b=1/2
f(x)=-1/2x²+1/2x