The preparation process is as follows:
y=ax？ +bx+c
=a(x？ +bx/a)+c
=a(x？ +bx/a+b？ /4a？ -B? /4a？ )+c
=a(x+b/2a)？ -B? /4a+c
=a(x+b/2a)？ +(4ac-b？ )/4a
For the general quadratic function y = ax 2+bx+c, its vertex coordinates are (-b/2a, (4ac-b? )/4a).
Brief introduction of quadratic function:
The basic expression of quadratic function is y=ax? +bx+c(a≠0). The highest degree of a quadratic function must be quadratic. The image of a quadratic function is a parabola, and its symmetry axis is parallel or coincident with the Y axis.
The expression of quadratic function is y=ax? +bx+c (and a≠0), which is defined as quadratic polynomial (or monomial).