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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi BarandaMan;

Which one are you having a problem with?

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**BarandaMan****Guest**

The whole problem, I cannot differentiate it.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi;

There is no such word as can't - pappym

Let's do it again.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**BarandaMan****Guest**

bobbym wrote:

Hi;

There is no such word as can't - pappym

Let's do it again.

Where do we start?

Could you not write it all out how you broke down each term and differentiated and show me so I can just try myself?

My exam is on January 8th and I don't have time

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Could you not write it all out how you broke down each term and differentiated and show me so I can just try myself?

My exam is on January 8th and I don't have time

I have already done that. Reminds me of the movie,

Sollozo: Get in the car!

Hagen: I do not have time for this...

Sollozo: Make time consigliori!

Unless you do it, you will not learn it. The 8th is many days away. The Japanese would say it is an eternity. Many things can happen till then.

You seemed to have got it before, did you forget how?

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**BarandaMan****Guest**

bobbym wrote:

Could you not write it all out how you broke down each term and differentiated and show me so I can just try myself?

My exam is on January 8th and I don't have time

I have already done that. Reminds me of the movie,

Sollozo: Get in the car!

Hagen: I do not have time for this...

Sollozo: Make time consigliori!

Unless you do it, you will not learn it. The 8th is many days away. The Japanese would say it is an eternity. Many things can happen till then.

You seemed to have got it before, did you forget how?

Hehehe! Thank you for your patience

I know but in terms of the module it is obviously 3 lines of one out of 22 lectures which has much more stuff that I cannot cover

I didn't forget anything from last time, just we nearly differentiated one of the terms.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Which term is remaining? I will post that for tomorrow.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

We found two of them =0. The third one we spent some time on, we got a result, then we have to put it over 'P' but I don't know why. And the last one we haven't yet begun.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi;

Since we are differentiating with respect to Pi, everything else is a constant.

Can you differentiate what is boxed off with respect to Pi?

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

Ok, yes, that is -nPi^(-n-1).

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

That is correct, now you only have to clean up the other term.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

So how does that term look (the one we just differentiated?)

Is it:

(nWYPi^(-n-1))/PP^(-n) = (nWYPi^(-n-1))/P^(-n+1)??

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

I think you lost a minus sign.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

where? can you post it?

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi;

You should end up with this.

**In mathematics, you don't understand things. You just get used to them.**

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**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,891

Hi bobbym

It looks like that is what he/she got...

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi;

Yes, I know but he has to know that too.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

bobbym wrote:

Hi;

Since we are differentiating with respect to Pi, everything else is a constant.

Can you differentiate what is boxed off with respect to Pi?

Bobby, with all due respect, you are making this very difficult for me.

My answer to this question, which I just posted, you said I was missing a minus sign...then you posted your most recent answer, which completely contradicts what I said (so I must be wrong on the previous differentiation).

I need someone to break it down for me and show that the answer I provided at the beginning is correct. If you cannot do that, please stop trying to make me 'see the light' as it were, with all due respect, because I am getting frustrated that we are not communicating well enough and all this is doing it leading to confusion. If you are choosing not to help me, please do not reply.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi;

You are missing the point of the comment. That was an honest mistake by me. I make them too. You have to know when you are right. In mathematics we can prove things for ourselves.

I need someone to break it down for me and show that the answer I provided at the beginning is correct. If you cannot do that, please stop trying to make me 'see the light' as it were, with all due respect, because I am getting frustrated that we are not communicating well enough and all this is doing it leading to confusion.

I am frustrated too but seem to have that under control. This is about the third time I have done this particular part of the problem. There is no breaking it down. You have some constants and a single variable to differentiate. For that you use the power rule. I have showed you this several times.

The last time you told me to just give you the answer because you do not have time to learn this. I have done that too. Also earlier, and this is exasperating, you said you got it. I forgot about the whole thread. Then you came back and said you do not understand it, so I did it again.

I also remember telling you that coming in sporadically for 2 minutes is not enough for me to teach you how. I can show you but you need to be here to learn it.

Mathematics is a prime subject. It is number one in difficulty, you are treating it as a side course. It takes 100% of my effort everyday.

Tell me what you want and I will do it. I can not do anymore than that. I can show you but only you can learn it.

One more thing, if you can argue with me about that differentiation like that then you know how to do it and I have been successful in teaching you no matter how irritated it made you. So please bear with my methods, they work!

I have taught two people and both of them are now better than I am at math. I am teaching a third person...

Let's do the 4th and last part.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

But the third term is still undone and I keep thinking that I am doing it correctly and then writing it up neat just for you to post something completely different so I get the feeling you are purposely doing this.

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

Hi;

I am not doing anything on purpose. For one thing I can not always understand your input. When you do not latex math it is difficult to read.

Different methods give answers that are in different forms. They are equivalent. I have checked all of yours for equivalency with mine.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

bobbym wrote:

Hi;

You should end up with this.

bobbym wrote:

Hi;

Since we are differentiating with respect to Pi, everything else is a constant.

Can you differentiate what is boxed off with respect to Pi?

So these two things, are they not different? Which is correct? I showed what I got by differentiating the bottom and wrote it out, it does not equal the thing you posted

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,953

They are different for a reason. One is differentiated the other is not. One is the question and the other one is the answer.

Your answer is also not simplified. In the beginning of this you differentiated it okay but then could not simplify it.

I will tell you what I will do. I will leave your thread open and someone else will help you.

**In mathematics, you don't understand things. You just get used to them.**

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**BarandaMan****Guest**

bobbym wrote:

They are different for a reason. One is differentiated the other is not. One is the question and the other one is the answer.

Your answer is also not simplified. In the beginning of this you differentiated it okay but then could not simplify it.

I will tell you what I will do. I will leave your thread open and someone else will help you.

You see how unhelpful you are being?

You TOLD me to differentiate the thing I just posted, I did it, I cannot simplify it, that is the whole point of this entire thread. I cannot simplify things, instead of helping me, you just tell me things like 'one is differentiated the other is not'. Thanks for all your help...I used to think you were a really good teacher. Not all students are the same so you must adapt your methods. Best wishes then.

**BarandaMan****Guest**

Just lock the thread you have killed this forum for me. Thanks for the help.