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#1 Re: This is Cool » n^2 » 2013-11-29 13:24:43

Thanks bobby smile I think the symmetry is pretty cool!

#2 This is Cool » n^2 » 2013-11-29 06:49:30

Replies: 8

big_smile I have just realized

#3 Re: Help Me ! » integration » 2009-03-12 04:07:32

The finite region is [0,4]:


Expand f(x):


edit: added graph

#4 Help Me ! » Taylor polynomial » 2008-11-27 14:12:12

Replies: 1

Hi. I'm doing something wrong here but I can't find out what it is.

Use Taylor's theorem to determine the degree of the Taylor polynomial for ln(1-x) required for the error in the approximation of ln(0.75) to be less than .001.

(I assume it is centered at a = 0)


Taylor polynomial:



Now I evaluate the polynomial for x=0.25

At this point I plotted f^n+1 and saw that

So this should give me the answer

I get n>=3 but the book says n>=4. Where did I go wrong? sad

#5 Re: Help Me ! » What am I doing wrong? » 2008-11-24 13:21:34

Ahh I didn't know that

were the nth roots of unity. Now it makes perfect sense. Thanks!


#6 Re: Help Me ! » What am I doing wrong? » 2008-11-24 10:02:29

Hi Daniel. I don't get this:

Could you explain it please? :)

#7 Re: Help Me ! » please help me with this problem » 2008-11-19 21:06:13

Hi. You mean you want to simplify it?

#9 Re: Help Me ! » Limit » 2008-10-30 11:14:53

mathsyperson wrote:

(To be honest, I wouldn't be confident about doing that usually. I cheated and evaluated the function for large values of n. It converged to e², and I made the above post with that knowledge.)

I don't know if this is what you mean, but I tried this in maple: seq(limit((1+i/n)^n, n=infinity), i=1..10);

It outputs e^i.

#10 Re: Help Me ! » Limit » 2008-10-30 11:05:13

You can rewrite the numerator as n² - n + 1 + 2n

Oh I missed that, I understand it now! Thank you big_smile

#12 Re: Help Me ! » Limit » 2008-10-30 09:15:51

Thanks mathsyperson. I don't understand why the base is approximated by 1 + 2/n. Could you please explain me that part?

#13 Help Me ! » Limit » 2008-10-30 08:02:54

Replies: 6

Hi! Could you help me calculate this limit?

#15 Help Me ! » Integral » 2008-10-22 04:36:54

Replies: 3

I'm having a hard time with this one. How would you solve it? Maple says the answer is

But I have no clue how to get there.

#17 Help Me ! » diff(1/lnx) » 2008-10-22 02:56:29

Replies: 2

Hi. Could someone explain why this is so?

#18 Re: Help Me ! » Area between functions » 2008-04-21 07:08:13

Daniel123 wrote:

I can't see any flaw in my (now corrected) working, and I trust mathsy too, so hopefully you were right :).

The solution has just been published. We got it right! :)) thank you all for your help.

#19 Re: Help Me ! » Area between functions » 2008-04-20 01:41:09

Daniel123 wrote:

I have just worked through the correct working, and I get the same thing as you mathsy.

Hm, so you get to the same point. Maybe I wasn't wrong in the end? Thanks a lot for your help :)

#20 Re: Help Me ! » Area between functions » 2008-04-20 01:19:57

Daniel123 wrote:

Are you sure that what you have done isn't correct?

No, I won't be sure until April 29. But while I was working on this exercise I realized there was a teacher next to me staring at my exam. His face was like "what the hell is this guy doing?". I said to him, "this must wrong..." and then he smiled and walked away. So I assumed my answer was not correct.

#21 Re: Help Me ! » Area between functions » 2008-04-20 00:25:24

Daniel123 wrote:

No, I don't think so. On his diagram he has shaded the region that I used yellow.

Exactly what Daniel said (from x=3 to +infinity). Sorry if I wasn't clear.

My approach was to calculate the area under both functions so that:

This is what I did:

The integral diverges so the area is undefined.

I guess this would work if I was to calculate the area between f(x) and y=0, but not in this case :\ I don't know how to tell if f(x) converges on g(x).

#22 Help Me ! » Area between functions » 2008-04-19 08:20:46

Replies: 13

Hi! I just had a calculus exam where I was asked to calculate the area between:

I'm so disappointed cause I wasn't able to solve it :( So how would you do it?

#23 Re: Help Me ! » Integration » 2008-04-15 06:59:03

Oh well >_< partial fractions again. I'll follow your advice and try to learn it. Thanks.

#24 Re: Help Me ! » Integration » 2008-04-15 06:12:40

wow Dragonshade, that's way too complicated for me, thanks for the answer though :D I've just found out that I'm allowed to use partial fractions, so I guess I'll have to learn how to use them.

Just one more question. Maple says...

It must be obvious but I just can't figure out why.

#25 Re: Help Me ! » Integration » 2008-04-15 04:29:28

Thank you for your answer, Jane smile I could get the right answer this way, but I'm not supposed to use partial fractions. Is there a way I can do it without using this method?

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