Sysmsum gives wrong output

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

[Stephen23]

@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.

Answer 1

[Birdman]

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]

[Mohamed Musni]

is there any way to prevent this? i mean any different ways to give the limits for the symsum

[Birdman]

Yes, you can change the upper limit dependent on k as follows:

symsum(((((q.*t)./2).*h)+P)./t,k,1,m+k)

[Mohamed Musni]

Thank you. have a nice day :D