题目
Max与Min问题,
Suppose you have to use exactly 200 m of fencing to make ether one square enclosure or two separate square enclosures of any sizes you wish.what plan gives you the least area?the greatest area?要详解,
Suppose you have to use exactly 200 m of fencing to make ether one square enclosure or two separate square enclosures of any sizes you wish.what plan gives you the least area?the greatest area?要详解,
提问时间:2021-01-03
答案
Assume the side lengths of the two squares are a and b(when a or b equals 0, it is equivalent to making one enclosure). As the total length of the fencing is 200m, 4(a+b)=200, a+b=50->b=50-a.
The total area of the two squares will be a^2+b^2=a^2+(50-a)^2=2a^2-100a+2500=2(a-25)^2+1250
a has a value range of [0,50].
As a=25, b=25, it gives the min area 1250. The plan is to make two squares with side length of 25.
As a=50 or a=0, it gives the max area 2500. The plan is to make one square with side length of 50.
The total area of the two squares will be a^2+b^2=a^2+(50-a)^2=2a^2-100a+2500=2(a-25)^2+1250
a has a value range of [0,50].
As a=25, b=25, it gives the min area 1250. The plan is to make two squares with side length of 25.
As a=50 or a=0, it gives the max area 2500. The plan is to make one square with side length of 50.
举一反三
已知函数f(x)=x,g(x)=alnx,a∈R.若曲线y=f(x)与曲线y=g(x)相交,且在交点处有相同的切线,求a的值和该切线方程.
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
奥巴马演讲不用看稿子.为什么中国领导演讲要看?
想找英语初三上学期的首字母填空练习……
英语翻译
最新试题
热门考点
- 1人们模仿蒲公英发明了什么
- 2用含有字母的式子表示下面的数量关系 2的c倍少8是什么?比z少4的数是什么?比x多12的数是什么?
- 3数学计算题,能简算的简算,
- 41/3×(15+3/14) 42×(19/14-8/21) 1/5×1/10×75×7/15 9/10×4+2/5 简便计算四道.
- 5in Chinese means 有没有这样的说法]?
- 6已知log6(2)=a,试用a表示log3(6)具体步骤
- 7请问一下一个最简单却又最难的数学题1+1=2,为什么会等于2不等于3呢?或者其他的
- 8get sb a ride与give sb a ride的区别是什么
- 9总结条件循环结构的一般方法
- 10某校今年秋季七年级和高一年级招生总数为 500人,计划明年秋季七年级、高一年级招生总数比今年增加18%.