Find the time when a parabolic function starts to decrease.

1 次查看（过去 30 天）

显示更早的评论

Roger L 2016-10-2

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/305446-find-the-time-when-a-parabolic-function-starts-to-decrease

评论： Roger L 2016-10-3

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

Hello,

My task is to write a script that will find the time when a parabolic function (height, a function of time) reaches its max.

clear all
t=0;
for time=0:0.5:30;
    if height(time)>=height(time-0.5)
        t=t+0.5;
    end
end
disp(t)

height(time-0.5) wouldn't execute so here is my second code

clear all
t=0;
for time=0:0.5:30;
    e=0.5:0.5:29;
    time2=[0 e];
    while height(time)>height(time2)
        t=t+0.5;
    end
end
disp(t)

this code does not work either. How can i utilize max( ) function in here? And what is the best way to do this kind of loop?

Thanks!

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Walter Roberson 2016-10-2

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/305446-find-the-time-when-a-parabolic-function-starts-to-decrease#answer_237002

What is height here? If it is a vector then you cannot use height(time) you can only use height(SomePositiveIntegerIndex) . But once you have found the appropriate positive integer index, you can use it to figure out what the corresponding time is.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Walter Roberson 2016-10-2

在 MATLAB Online 中打开

[maxheight, idx] = max(height(time))

where time is a vector. Then time(idx)

Roger L 2016-10-3

thanks for that command, I haven't used it before. It gave me an index on the time vector corresponding to the seconds that I needed.

请先登录，再进行评论。

类别

MATLAB Mathematics Numerical Integration and Differential Equations Numerical Integration and Differentiation

在 Help Center 和 File Exchange 中查找有关 Numerical Integration and Differentiation 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by