30.It is given that the graph of y=(m-2)x^2+(2m+5)x+(m+1) cuts the x-axis at two points.
(a) Determine whether the value of m can be 2.Explain you answer
(b) Find the range of possible values of m
Quadratic Equation(一條)
2011-10-06 5:29 am
回答 (2)
2011-10-06 5:56 am
✔ 最佳答案
(a)the value of m cannot be 2sub m=2,
y=(2-2)x^2+(2*2+5)x+(2+1)
y=9x+3
it is not a quadratic function
(b)the graph cuts the x-axis at two points
so delta>0
(2m+5)^2-4(m-2)(m+1)>0
4m^2+20m+25-4(m^2-m-2)>0
4m^2+20m+25-4m^2+4m+8>0
24m+33>0
m>-11/8
as m cannot be 2,so m>-11/8 and m=/=2
參考: me
2011-10-06 6:33 am
Supplementary for (a),
For deg one function, it can never meet another deg one function (e.g. y=0) at two points.
For deg one function, it can never meet another deg one function (e.g. y=0) at two points.
收錄日期: 2021-04-13 18:16:56
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111005000051KK01072