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Yes, thats what I'm doing. Sorry

**amberzak**- Replies: 3

Statistics this time.

I have a poisson distribution, and I am just trying to work out my degrees of freedom.

I have 7 columns of data. I have the mean. I have not worked out the variance yet. But I do have the total frequency.

So does the total expected frequency count as a constraint

In other words, is my degree of freedom 7-1=6 or 7-2=5

(it does make a difference because 7-1 means that it is a poisson distribution and 7-2 means it isn't)

That thanks a million was to you both

(Sorry Stefy if that wasn't obvious).

You are both absolute stars

Thanks a million.

So your answer, bobby, that is the minimum? That is the answer?

So then l-x=l-[4l/(pi+4)]

= L*Pi/(pi+4)

Is that the answer? That's the minimum right? How do I find the max? I imagine it is just using the whole length of rope for a circle, but how to I prove that? I can prove that a circle and a square of a set perimeter, the circle will have the biggest area.

Can you just explain what you did please?

I'm guessing that we divide through by x to get it on its own.

Hey bobbym. Please see post above. How do I solve it equated to 0?

Right so I have got

So the df/dx is

Pray tell what do I do now?

(I know I have to equate it to mean 0, but what do I actually have to do?)

thanks. I obviously need to add x^2/16 to the end result you have there (I am guessing) and so do I do the cross multiplying?

Also, how do you so all that maths set up on the forum?

Thanks anon.

Sorry, I've got the deadlines looming and I've burnt myself out

Okay, what's the correct way to square it.

What did I do wrong?

How do I do that. Do I first need to get rid of the brackets? So it would be

x^2/16+Pi((L^2-x^2)/2pi^2)

?

Then where do I go? Can we take it a step at a time please?

**amberzak**- Replies: 29

A piece of string of length L is to be cut into two pieces. One piece is formed into a square, the other into a circle.

a)Where, if anywhere, would the string be cut to that the total area of the two shapes is a small as possible

Where, if anywhere, should the string be cut so the area is as large as possible

This is what I have:

I'm assuming that the maximum would be just a circle, but I don't know how I'd show that. And not sure how I'd do the minimum

It's working today

It's okay, my real name isn't amberzak.

What was the method you used bob? And thanks, you have been very helpful

The link you gave me doesn't work

Bob, I am guessing it's still answer in process. I get so far and then couldn't get further. I think the sec^3 theta tan theta is a hint.

**amberzak**- Replies: 19

By using the Substitution u=cot theta or otherwise, find the integral of cot ^4 theta d theta

My teacher says there is a really simple way to do this, so it shouldn't take hours.

He also gave us a hint of writing down sec^3 theta and tan theta, but I can't see how we can get to that.

Any ideas?

**amberzak**- Replies: 5

Hi

I can't figure this one out.

Let U = lnx

Do I tried to differentiate lnx by du. I got du=1/x dx. Then I know I need dx by itself, but not sure how to get to that.

Can anyone help me?

Thanks all

No, not really. Could you please go through that? I kind of see it.

Okay. so the first thing I need to do is find A and B as shown above?

Then, how do I integrate the fraction. My teacher said it was something to do with Partial Fractions, and did say if i couldn't do the question not to worry because I've not studied partial fractions before, but I would like to at least understand how the answer is derived.

I've never seen the x with the arrow before. What does it mean?

anonimnystefy, that is classic. I love it