题目
The equation of a curve is such that , where is a constant. The curve has minimum points at and .
Find the coordinates of the other stationary point of the curve.
题目中文翻译
一条曲线满足 ,其中 为常数。曲线在 和 处有极小值点。
求曲线上另一个驻点的坐标。
原卷通用作答要求
Answer all questions. You should use a calculator where appropriate.
You must show all necessary working clearly; no marks will be given for unsupported answers from a calculator.
Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place for angles in degrees, unless a different level of accuracy is specified in the question.
请回答所有题目。适当时应使用计算器。必须清楚展示所有必要的计算过程;仅给出计算器答案而没有过程,不予评分。除非题目另有精度要求,非精确数值答案保留 3 位有效数字,以度为单位的角度保留 1 位小数。
解答
解法一
思路
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积分一次后,两个极小点的一阶导数都为零,正好确定 与第一个常数。再积分并用已知高度求第二个常数。
答题过程
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Integrating gives . At and , respectively,
Adding gives , and then . Thus , so the other stationary point is at .
Integrating again gives . Since , we have , so . The other stationary point is .