Sysmsum gives wrong output
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For this code im getting output as below. But its multiplied with 3 in every term. What am I doing wrong here? Because I don’t need that multiplication with 3
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/169335/image.jpeg)
1 Comment
Stephen23
on 23 Jan 2018
@Mohamed Musni: please do not post screenshots. It is actually easier for us when you post real text: this includes the code and any error messages. Real text can be searched (or searched for), edited, and run. Screenshots are basically useless in most cases.
Accepted Answer
Birdman
on 23 Jan 2018
Actually, your code displays the correct output because you try to implement the series sum with respect to a different variable k, which is not included in any of your other symbolic variables. Therefore your series turns into something that multiplying a constant value with m, which is 3 in this case.
((((q.*t)./2).*h)+P)./t
>> [q1 + 10, (3*q2)/2 + 10, 2*q3 + 10]
As you see, q symbolic variable is not dependent on k, therefore your symsum will be multiplied by m directly. 3 comes from that.
symsum(((((q.*t)./2).*h)+P)./t,k,1,m)
>> [3*q1 + 30, (9*q2)/2 + 30, 6*q3 + 30]
3 Comments
Birdman
on 23 Jan 2018
Yes, you can change the upper limit dependent on k as follows:
symsum(((((q.*t)./2).*h)+P)./t,k,1,m+k)
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