一道英语的高中数学题,回答用中文就可以,The diagram shows the graph of a quadratic function(抱歉没有图).The graph passes through the points(6,0) and (p,0).The maxinum point has coordinates(0.5,30.25).(a) Calculate the value of p.(b) Given that the quadratic function has an equati
2019-04-13
一道英语的高中数学题,回答用中文就可以,
The diagram shows the graph of a quadratic function(抱歉没有图).The graph passes through the points(6,0) and (p,0).The maxinum point has coordinates(0.5,30.25).
(a) Calculate the value of p.
(b) Given that the quadratic function has an equation y=-x^2+bx+c,find b and c.
优质解答
①假设那个二次方程的表达式为y=－a﹙x-6﹚﹙x-p﹚,其最高点的横坐标为﹙6＋p﹚／2,所以﹙6＋p﹚／2=0.5,p=－5；将x=0.5带入,得a=1
②将p=－5带入y=－﹙x-6﹚﹙x-p）中,与y=-x^2+bx+c比较得b=1,c=30
①假设那个二次方程的表达式为y=－a﹙x-6﹚﹙x-p﹚,其最高点的横坐标为﹙6＋p﹚／2,所以﹙6＋p﹚／2=0.5,p=－5；将x=0.5带入,得a=1
②将p=－5带入y=－﹙x-6﹚﹙x-p）中,与y=-x^2+bx+c比较得b=1,c=30