The previous equation can be drawn in rectangular coordinates, and then a series of concentric circles with the origin as the center intersect with the previously drawn circle. The maximum diameter is 4, so the maximum value is 2.
2 . f '(0)= b & gt； 0; And according to the meaning of the question: a>0; (4ac-b^2)/(4a)>； 0
Therefore, AC>B 2/4, so f' (o)/f (1) = b/(a+b+c).
3.f(0)>0; f( 1)& lt； 0; Get a+b >; - 1; 2a+b & lt； -3; Think of them as straight lines (y =-1-x; Y=-3-2x) Draw their effective areas in Cartesian coordinates, and let a straight line b = Ka (y = Kx); It is known that the minimum slope of a straight line is -2, and the maximum slope is infinitely close to-1/2.