高中数学函数题目 在线等答案或中文翻译题目是英文版本的.求题解,需要详细过程.或者是题目的中文翻译,都可以1. Sara was sitting on a swing, talking about the mathematics she had been doing at school and swinging gently to and fro. She noticed that the period of one complete swing was 3 seconds and that if she did nothing to keep going, the amplitude of her motion decreased from 1 metre to 50cm in 2 minutes. If Sara’s horizontal displacement is x metres after t second, find a function of the form x=Ae-ktco
高中数学函数题目 在线等答案或中文翻译
题目是英文版本的.求题解,需要详细过程.或者是题目的中文翻译,都可以
1. Sara was sitting on a swing, talking about the mathematics she had been doing at school and swinging gently to and fro. She noticed that the period of one complete swing was 3 seconds and that if she did nothing to keep going, the amplitude of her motion decreased from 1 metre to 50cm in 2 minutes. If Sara’s horizontal displacement is x metres after t second, find a function of the form x=Ae-ktcos nt to describe this motion. Find an expression for Sara’s horizontal velocity after t seconds.
2. Show that the area under the curve y=x2-1/12 from x=r-1/2 to x=r+1/2. By considering the area under this curve from x=1/2 to x=n+1/2, show that :1²+2²+3²+……….+n²=n(n+1)(2n+1)/6
3. Suppose that x has density f(x)=12x²(1-x) for 0
1.莎拉坐在秋千上想着她在学校里做过的数学题。秋千慢慢地来回荡来荡去。她注意到：秋千来回荡的完整周期是3秒钟，如果她不用力使秋千运动，她所坐的秋千的振幅会在2分钟内从1m减少为50cm. 假设莎拉t秒后的水平位移为x,找出一个类似于x=Ae-ktcos nt 的函数来描述这种运动。求莎拉t秒后的水平速度。
（只看得懂第一题哈）
1. Sara was sitting on a swing, talking about the mathematics she had been doing at school and swinging gently to and fro. She noticed that the period of one complete swing was 3 seconds and that if s...