help me to do those questions:
1)若二次方程 (k - 2)x^2 - 10x + 25 = 0有實根，求常數k 值的範圍。
2)解方程 4x^2 - 4kx + k^2 = 0
3)設f(x) = x^2 -1，則 f(x + 1) =?
4)設f(x) = x(x + 1)(x + 2)，則 f(x) - f(x - 1)=?
5)求函數 y=4x^2 - 11x - 3 的圖像的 x 軸截距和 y 軸截距。
盡量解答!!!
可以ge話俾埋過程ar~~
thanks^_^
maths homework
2007-02-21 2:31 am
回答 (1)
2007-02-21 2:41 am
✔ 最佳答案
1k-2>=0, k>=2
ALSO
discriminant>=0
100-100(k-2)>=0
1-(k-2)>=0
3>=k
So 2<=k<=3
2
4x^2 - 4kx + k^2 = 0
(2x-k)^2=0
2x-k=0
k=2x or x=k/2
3
f(x) = x^2 -1
f(x + 1)
=(x+1)^2-1
=x^2+2x
=x(x+2)
4
f(x) = x(x + 1)(x + 2)
f(x) - f(x - 1)
=x(x + 1)(x + 2)-(x-1)(x)(x + 1)
=x(x+1)(x+2-x+1)
=3x(x+1)
5
y=4x^2 - 11x - 3
代y=0
4x^2 - 11x - 3=0
(4x+1)(x-3)=0
x=-1/4 或 3
代x=0,y=-3
x 軸截距是-1/4, 3 ;y 軸截距是-3
收錄日期: 2021-04-23 16:40:33
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