设f(x）=ax^2+bx+c∵图像过（0,0)∴c=0f(x)=ax^2+bxf(x+1)=a(x+1)^2+b(x+1)...(1)f(x)+x+1=ax^2+bx+x+1...(2)(1)=(2)a(x^2+2x+1)+bx+b=ax^2+(b+1)x+1ax^2+（2a+b)x+(a+b)=ax^2+(b+1)x+12a+b=b+1 a=1/2a+b=1 b=1/2解...