Homework Section

[Malcolm]

maybe for some education? if you cheat your way through school when you get to the end of it you'll be in the top sets, and actually know nothing, then you'll miserably fail your main test

Remember kids: It's only cheating if you get caught!

 :razz:

[Chuck_Norris]

How many uneven numbers can there be from the number 3694 if the numbers can each only be used once?

The answer is 32... how do I get it? :conf:

Not exactly homework

not sure if its correct but...

3 isn't a even number
6 is a even number (divided by 2 = 3)
9 isn't a even number
4 is a even number (divided by 2 = 2)

3 and 2 = 32 :p

[Cutt3r]

The nos 3 and 9 have to be in the units place. So we can interchange the tens, hundreds and thousands place

Here we use permutations and combinations. i will tell you what i remember from 9 years ago. Forgive me if it is a lil wrong but I believe you can work the rest out.

Lets start with 2 digit numbers. If 3 is in the units place we can have 3 other numbers (6,9,4) in the tens place. That is 3_p1 or 3*2/2*1(3-1=2) = 3---->a

Now we put 9 in the units place. You will get 3 again as above. ---->b

Now we look for 3 digit numbers. We keep 3 in the units place and use a permutation for the tens and hundreds digit numbers. We have 3 other numbers we can use, besides 3. So we use the permutation 3_p2 ie 3*2/1 =
6.--->c

Now replace the units digit (3) with 9. Similar to (c) we get 6 again. ---->d

Now we again put 3 in the units place. We use a permutation for the tens, hundreds and thousands place. We have 3 numbers for this and the order matters so the permutation is 3_p3 ie 3*2/(3-3)! = 6/1 = 6.---->e

Similarly we get the answer as 6 if we put 9 in the units place.---->f

 Note that 0! and 1! are both = 1.

Now a+b+c+d+e+f = 3+3+6+6+6+6 = 30. So how did Gimli get 32?

Simple. We have not taken the two odd numbers into consideration. 3 and 9 by themselves, as single digits were not taken for the above. Therefore, the final asnwer is 32

[Jubin]

cutter, everything is sweet and all, but you start repeating your actions

Now we look for 3 digit numbers. We keep 3 in the units place and use a permutation for the tens and hundreds digit numbers. We have 3 other numbers we can use, besides 3. So we use the permutation 3p2 ie 3*2/1 =
6.--->c

is actually the same as

Now we again put 3 in the units place. We use a permutation for the tens, hundreds and thousands place. We have 3 numbers for this and the order matters so the permutation is 3p3 ie 3*2/(3-3)! = 6/1 = 6.---->e

or isn't it?

[Cutt3r]

Not exactly. In the first quote i was talking about a 3 digit number with '3' in the units place(We keep 3 in the units place and use a permutation for the tens and hundreds digit numbers). Like 643 for example.
In the second quote I am talking about a 4 digit number (We use a permutation for the tens, hundreds and thousands place)like 9463.

However if you are talking about 3_p2 and 3_p3, the answer to them maybe the same but as i did state, the denominator is 0! and 1!. The denominator is different but both have the same answer ie 1. That is why the answer is 6 in both cases.

[rJCaiG]

Could we only ask for help with little parts and not whole assignments? Cheating is not cool....

[Custom]

Hello again
I am stuck in math
I got something about "logistic growth".
I need to know what importance the functions A, B, and C have in the graph (check picture). 
Would really appreciate it if anybody could explain it for me ?

Thanks for reading, and for your help

Best regards
Custom

[Jubin]

Hello again
I am stuck in math
I got something about "logistic growth".
I need to know what importance the functions A, B, and C have in the graph (check picture). 
Would really appreciate it if anybody could explain it for me ?

Thanks for reading, and for your help

Best regards
Custom

Ok, let's take logically.

First of all the constant C - the bigger is constant C, the bigger is f(x). for example 5/1+a*e^-bx is always bigger then 3/1+a*e^-bx. Take C as the number of cakes you have and (1+a*e^-bx) the number of people on your party. It is logical that the more cakes you have, the bigger slice everybody gets.

Constant A - the bigger is constant A, the more crowded it gets. let's say you always have 5 Cakes( C=5). So the people at first was 2( A=2), equation would be f(x)= 5/1+2*e^-bx. It would be 1+2 people. but now, when we change A bigger, let's say to 3 (A=3) we would get more people, and everybody would get less cake, and someone has to go to store, to get more.

Constant B - The bigger is constant B, the less crowded the place gets. So take B as the constant of farting. The more people fart, the less people stays in the room. In mathematical, let me take only the part of e^-bx. If the B=-7 then -(-7)*x= 7x therefore we get e^7x. If B=0 then -(0)*x=0 therefore we get e^0(=1). If B=7, then -7*x=-7x therefore we get e^-7x = 1/e^7x.

If this is what you asked?

[Cutt3r]

Jubin is math awesomeness the math god :D

[Jubin]

Jubin is math awesomeness the math god :D

And the truth is that I am always waiting for mathematicians to solve equations for me.

[Alsatian]

My god.. I would expect this is the kind of maths I will be learning soon..  :conf:

[Custom]

Hello again
I have some problems with understanding complex numbers..
Pictures uploaded.
And besides the pictures, can somebody proove the following;
Let a be a real number. Evidence that a/i = -ia 

[Jubin]

a/i=-ia. Now from the right side take that i to the left side and you get a/(i*i)=-a. We know that i^2= -1 therefore we get a/(-1)=-a => -a=-a. Everything matches don't know any better way to proof it.

 :ps: I am waiting for Ghost to come and say I'm wrong

[Matthew_Cipricla]

Alirhgt Jubin, here is a difficult one (for me atleast). Its not really homework but I would really like to know the answer. How do you solve a rubik's cube with mathemtics? I know it is possible since there is a robot who solves them with mathematic eqoutations. But I am not sure how..... And I am pretty good at algebra too... Do you know the answer? Or like direct me to some other webistes would also be great.

[~Legend~]

Great idea!!!!
If anyone is stuck on any subjects, please feel free to contact me!