Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#26 Help Me ! » linear algebra » 2008-11-29 04:03:09

GemmaJ1988
Replies: 5

can anyone give an example of a linear map such that Im(f)=Ker(f)
im(f)=image of f
ker(f)=kernal of f

#27 Re: Help Me ! » factorise » 2008-11-29 02:17:51

i've factorised it to get:


is it possible to factorise again?

#28 Help Me ! » factorise » 2008-11-29 01:00:59

GemmaJ1988
Replies: 5

hey can anyone factorise the following equation:

#29 Help Me ! » simultaneous eqn » 2008-11-28 09:39:21

GemmaJ1988
Replies: 1



Im trying to solve this system of simultaneous equations
as solutions i got:




Im not sure if these solutions are correct can anyone think of others?

#30 Help Me ! » Even or Odd function? » 2008-11-27 03:57:53

GemmaJ1988
Replies: 1

i have the following function:


where

Does anyone know whether this function is even or odd?
i assumed it was odd, but does this depend on the value of k?

#31 Help Me ! » help me simplify » 2008-11-25 06:06:24

GemmaJ1988
Replies: 1


ive attempted to rewrite this as the following:

does anyone know whether i've simplified this correctly?
please help xxx

#32 Help Me ! » Poisson distribution » 2008-11-24 08:06:15

GemmaJ1988
Replies: 2

i have the following question:

An experiment on 25 cars is carried out. 15 of these cars are classed as flawed. 10 are classed as flawless.
assuming this has a poisson distribution


find the probability that a car has a flaw in terms of

my solution so far:
ive taken the average no of flaws to be 15/25=0.6
So


so the prob of a car having a flaw is:

so

As the question asked for the probability that a car has a flaw in terms of


im not sure if my solution is what the questions actually asking for
please help!

#33 Help Me ! » fluid dynamics » 2008-11-18 05:56:59

GemmaJ1988
Replies: 1

air at pressure p=p0 is above a layer of oil of depth A and density D1.
the oil lies on water of density D2>D1.
find the pressure at a distance B>0 below the oil water boundary.

Ive looked at examples of pressure below water without an oil layer and i can see clearly how the fundamental equation of hydrostatics can be used:


where D=density and K is the vector component

but im not quite sure how to apply this to this type of question.
Here the pressure is a continuous function of position and the density varies.
can anyone please help me understand this example

#34 Re: Help Me ! » linear algebra » 2008-11-17 23:50:22

i can see that but i dont understand where i get ad-bc=0 from

#35 Help Me ! » linear algebra » 2008-11-11 04:25:43

GemmaJ1988
Replies: 8

suppose


If ad-bc=0 show that v and w are linearly dependent

does anyone know how i do this.
i know to show something is linearly independent i would do as follows:


then try and solve the simultaneous eqns.
but seen as  v and w are linearly dependent im a little lost please help

#36 Re: Help Me ! » primes » 2008-11-05 11:15:28

so i've looked up the fundamental theorem of arithmetic and ive tried to apply this to n
i got



if we set



does this seem remotely along the right lines?

#37 Re: Help Me ! » primes » 2008-11-05 02:16:19

is n not already expressed as its product of distinct primes then?

#38 Help Me ! » primes » 2008-11-04 09:10:20

GemmaJ1988
Replies: 5

i have the following question
write

as a product of distinct primes.
does anyone know what this is actually asking me to do.
please help

#39 Re: Help Me ! » graph theory » 2008-11-04 02:26:19

yes kn is the complete graph of order n
so kn is of odd order.
but i still dont understand how to show ri is not equal to bi

#40 Help Me ! » graph theory » 2008-11-04 01:34:59

GemmaJ1988
Replies: 3

suppose that n=3 mod4 and we colour the edges of kn red or blue
take ri to be the no. of red edges and bi=n-1-ri to be the no. of blue egdes
show that it is not possible to have ri=bi for all i
1<=i<=n

does anyone know how i would go about answering this question.
Im unsure what the value of n would be as i dont really know what n=3 mod 4 equals. please help

#41 Help Me ! » combinatorics » 2008-10-31 23:49:27

GemmaJ1988
Replies: 1

hey
i've found a question in the book "a course in combinatorics" which i need help solving
problem:
"The girth of a graph is the length of the smallest polgon in the graph. Let G be a graph with girth 5 for which all vertices have degree>=d. show that G has atleast d^2+1 vetices."

can anyone please help me to understand this question

#42 Re: Help Me ! » integration » 2008-10-30 04:44:14

ok so i've done this and i've got


does this seem correct?

#43 Re: Help Me ! » integration » 2008-10-30 03:12:38

im not sure how to integrate


though. can anyone show me how??

can i rearrange this to be


then integrate

i feel this might complicate things

#44 Re: Help Me ! » integration » 2008-10-30 02:59:26

Thank you that was actually very simple!
another integration problem which has left me unsure is the following


i know the following is true

can i just aply this to get:

does anyone know if this is correct? please help

#45 Help Me ! » integration » 2008-10-29 08:40:42

GemmaJ1988
Replies: 7

hi i'm not sure wether im integrating the following function properly


i know this function integrated with respect to x in lnx
if i integrate it with respect to y do i get lnxy
please help, will be very much appreciated!!

#46 Help Me ! » Statistics » 2008-10-24 21:14:42

GemmaJ1988
Replies: 0

can anyone show that


for a geometric distribution where p is the probability of success.
Please help

#47 Help Me ! » Isomorphic graphs » 2008-10-14 06:05:35

GemmaJ1988
Replies: 0

I have a revision question which asks me to prove two graphs are isomorphic.

from the definition i know that 2 graphs G and H are isomorphic if there exists a bijection


such that if there are k edges between x,y in V(G) then we have k edges between w(x),w(y) in v(H)

Does anyone know what steps i would take to prove they are isomorphic?
please help

Board footer

Powered by FluxBB