How to convert this equation to MATLAB code?

Question

JM 2020-9-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/599386-how-to-convert-this-equation-to-matlab-code

编辑： JM 2021-6-30

采纳的回答： John D'Errico

I am having difficulty writing this long equation into matlab code, please advise

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Adam Danz 2020-9-24

编辑：Adam Danz 2020-9-24

在 MATLAB Online 中打开

Very close!

One critical mistake.

This section is wrong. You're doing A/B*C but that's not how that part of the equation is defined.

  (((x1.^2)*9.81)/25*(cos(30)))
%  -------A------ B  ----C----

Two cautionary comments

Are you sure the last constant is 3.5 rather than 35?
The "cos(30)" and "tan(30)" in the equation is likely in reference to degrees so you'll either need to convert 30deg to radians (see deg2rad) or use cosd() & tand() which receives degree inputs.

Some very minor points

No need for the outer brackets
The brackets here are unnecessary but if they help you, that's totally fine: (x1.^2)*9.81; You can review Matlab's Operator Precedence.
No need for these outer brackets, they are confusing: (cos(30))
There's no need for the outer brackets aound the fraction that contains parentheses in the image you shared but, as with point #2, sometimes those brackets are helpful for perceptual grouping and I would probably keep them.

Result

After making those changes, including the interpretation of degrees and that the constant at the end is 35, the first few elements of the row-vector outptut are

y1 = [ 35 35.155 35.268 35.339 , ...

*Posted before seeing John D'Errico's answer.

Adam Danz 2020-9-24

Sounds like you figured it out! Socially distant 3-way high-five!

Rik 2021-4-20

I recovered the removed content from the Google cache (something which anyone can do). Editing away your question is very rude. Someone spent time reading your question, understanding your issue, figuring out the solution, and writing an answer. Now you repay that kindness by ensuring that the next person with a similar question can't benefit from this answer.

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Answer 1

John D'Errico 2020-9-24

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https://ww2.mathworks.cn/matlabcentral/answers/599386-how-to-convert-this-equation-to-matlab-code#answer_499990

编辑：John D'Errico 2020-9-24

在 MATLAB Online 中打开

Well, you did make an effort, and it was pretty close. But did you read my response?

Did you read the help for tand and cosd? Why not? There was a reason I wrote that hint. They are different from tan and cos. tan and cos work in radians. But you seem to be using DEGREES. So you NEED to use cosd and tand.

Next, you MULTIPLIED by cos(30). While you may think that