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1.二次函数y=ax~2+bx+c的图象和性质(1)当a>0时,函数y=ax~2+bx+c图象开口向上;顶点坐标为(-b/(2a),(4ac-b~2)/4a),对称轴为直线x=-b/(2a)去.当x<-b/(2a)时,y随着x的增大而减小;当x>-b/(2a)时,y随着x的增大而增大;当x=-b/(2a)时,函数取最小值y=(4ac-b~2)/(4a).(2)当a<0时,函数y=ax~2+bx+c图象开口向下;顶点坐标为(-b/(2a),(4ac-b~2)/(4a)),对称轴为直线x=-b/(2a).当x<-b/(2a)时,y随着x的增大而增大;当
1. Image and Properties of Quadratic Function y = ax ~ 2 + bx + c (1) When a> 0, the function y = ax ~ 2 + bx + c The image is open upward; the vertex coordinates are (-b / (2a), (4ac-b ~ 2) / 4a) and the axis of symmetry is a straight line x = -b / (2a) .When x <-b / (2a), y decreases with increasing x ; When x> -b / (2a), y increases with the increase of x; when x = -b / (2a), the function takes the minimum y = (4ac-b ~ 2) / (2) When a <0, the function y = ax ~ 2 + bx + c has the image opening facing downward; the coordinates of the vertices are (-b / (2a), (4ac-b ~ 2) / (4a) , The axis of symmetry is a straight line x = -b / (2a). When x <-b / (2a), y increases with increasing x