taro

440 Reputation

12 Badges

5 years, 361 days
Maple is to me difficult. The first version I bought was Maple9, and it was more than 15 years ago. But, I couldn't use it, feeling it too difficult. But, three years ago, I thought Maple might be helpful to my study, and since then, I have continued to learn Maple. As I got able to read the Maple help, I think that I could get to use maple better now than before. But, I feel that I am a beginner yet.

MaplePrimes Activity


These are replies submitted by taro

@Adri van der Meer 

 Thank you for your reply. I m sorry to say that you might misunderstand the problem I wrote.

With the calculation you wrote, that is,
v:=Int(q^2,i=0..M)^2;
diff(v,q);
what I obtained was

2*Int(q^2, i = 0 .. M)*Int(2*q, i = 0 .. M)

This is not right, because the answer has to be

2*Int(q^2, i = 0 .. M)*2*q

 q is considered to be a vector with infinite dimension. And, for its particular element q(i), I wanted to differentiate the integral.

 Take care.

 Taro

@J4James 

Hello,

 I wanted to differentiated u with respect to q(i) with the particular i.
The reason I used q(i) not q[i] is that it is necessary for integration.
And, on the other hand, q(i) becomes variable, for a particular i.
I wanted to differentiate u with that q(i).

 Originally, I wanted to calculate this.

 v:=Int(q(i)^2,i=0..M)^2;
 dv:=diff(v,q(i));

which shows an error message.

So, I modified this as

> v:=(Int(q(i)^2,i=0..M)+q[k]^2)^2;
>diff(v,q[k]);

Then, 

4*(Int(q(i)^2, i = 0 .. M)+q[k]^2)*q[k]   (*)

appears. I don't like the expression of (Int(q(i)^2, i = 0 .. M)+q[k]^2) in the (*), and haven't been able to modify this to 4*(Int(q(i)^2, i = 0 .. M). And, with algsubs, q[k] which is in a expression outside of the original expression v, is modified, which is not good for me.

But, I think that my problem might have been settled down owing to you.

Thank you very much.

taro

@J4James 

 

Thank you for your reply. I did as you kindly taught me.

But, the answer I could obtain through your codes was M not 1.

1 is the correct answer, which I couldn't obtain.

 

Take care.

 

taro

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