EX.5A
12.There are graphs of the functions y=2x^2 and y= -x^2.
(b)(i)write down the axis of stmmetry and the coordinates of the vertex of each of the graphs of y=5x^2 and y= -1/2(x^2).
(ii)write down the maximum or minimum value of each of the functions y=5x^2 and y= -1/2(x^2).
F.4 MATHS
2012-09-24 4:06 am
回答 (2)
2012-09-24 4:19 am
✔ 最佳答案
b) i) y = 5x², y = -½x²:Axis of sym.: x = 0.Coor. of vertes: (0, 0).ii) Min. value of y = 5x²: 0.Max. value of y = -½x²: 0. I HOPE THIS CAN HELP YOU!~ ^_^
參考: My Maths World
2012-09-24 5:04 am
12.
(b)(1)
y=2x^2
Through differenciation:
Df(kx^n)=knx^(n-1)
Df(2x^2)=4x
therefore, axis of symmetry should be 4x=0，x=0
coordinates of the vertex :(0,0)
y= -1/2(x^2).
Through differenciation:
Df(kx^n)=knx^(n-1)
Df(-1/2(x^2))=-x
therefore, axis of symmetry should be -x=0，x=0
coordinates of the vertex :(0,0)
(b)(2)
In y=5x^2，as 5 is a positive number，therefore the maximum value is 0.
In y= -1/2(x^2) ，as-1/2 is a negative number，therfore the minimun value is 0.
即使您未學微分(Differenciation)，只要您心水清，也會知道拿5x^2及-1/2(x^2) 去complete square，x的結果也是0。
2012-09-23 21:46:12 補充：
sorry，打錯字，微分的英文名是Differentiation。
(b)(1)
y=2x^2
Through differenciation:
Df(kx^n)=knx^(n-1)
Df(2x^2)=4x
therefore, axis of symmetry should be 4x=0，x=0
coordinates of the vertex :(0,0)
y= -1/2(x^2).
Through differenciation:
Df(kx^n)=knx^(n-1)
Df(-1/2(x^2))=-x
therefore, axis of symmetry should be -x=0，x=0
coordinates of the vertex :(0,0)
(b)(2)
In y=5x^2，as 5 is a positive number，therefore the maximum value is 0.
In y= -1/2(x^2) ，as-1/2 is a negative number，therfore the minimun value is 0.
即使您未學微分(Differenciation)，只要您心水清，也會知道拿5x^2及-1/2(x^2) 去complete square，x的結果也是0。
2012-09-23 21:46:12 補充：
sorry，打錯字，微分的英文名是Differentiation。
參考: me
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