標題:
Partial variation: x = 0?
發問:
2004 CE Maths Paper 1 Q10It is known that y is the sum of two parts, one part varies as x and the other part varies as the square of x. When x = 3, y = 3 and when x = 4, y = 12.(a) Expressy in terms of x. (4marks)(b) Ifx is an integer and y
最佳解答:
此文章來自奇摩知識+如有不便請留言告知
You are right that for (a), the solution is y = 2x^2 - 5x. In (b), we then set 2x^2 - 5x
其他解答:
if y varies as x, then x and y must be bothnon-zero. this is correct. but in this case, you do not need to reject x=0 because 0 is an integer. x=0 is only one of the possible values. when x=0, y=0., it is correct. if y varies as x, then x and y must be bothnon-zero. means y=kx+kx2, the x here can not be zero because x is a variation, when you put different values of x, you will get different values of y.
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