# Recent content by Dollydaggerxo

1. ### Average Percentages over 3 years

I am just having trouble with percentages. Lets say a town has a population of 1,000,000 in 2006 1,200,000 in 2007 1,800,000 in 2008 The percentage increase from 2006-2007 is 20% 2007-2008 is 50% So, what I want to work out is the AVERAGE percentage per year. The increase...
2. ### Fourier Series coefficients, orthogonal?

Okay I have got it. Thanks!
3. ### Fourier Series coefficients, orthogonal?

Homework Statement Hello. I need help with orthogonality of the fourier series coefficients. I know you can use the dirac delta function, (or the kronecker function) in the orthogonality relationship. I want to try and see the derivation using complex form rather than sines and cosines...
4. ### Elevators and Potential

cant you do the absolute value of it as surely same power would be needed to go from 1 to 2 as 2 to 1
5. ### ODE phase portrait

for any values of C?? all i am getting is what looks like a square graph translated a lot im not sure what its mean to look like thanks
6. ### ODE phase portrait

i see -- ok sorry. so \frac{y^2}{2} = \frac{x^4-2x^2}{4} + C ?? i still dont really know what to do with it though forgive me!! thanks again
7. ### ODE phase portrait

thanks for the reply!!! do you mean just straight forward integrate it w,r,t, x for example it would be \frac{x^4 - 2x^2}{4y} ?? then what would i do with that though?? thanks so much for your help
8. ### ODE phase portrait

Homework Statement i need to create the phase diagram for the equation \ddot{x}=x^{3}-x using MATLAB Homework Equations Well i have worked out that there is a centre point at 0,0 and a saddle point at -1,0. The Attempt at a Solution i found a site on the internet which shows me...
9. ### Primitive Polynomials

Haha ok just ignore me, i think i get it now anyway. many thanks for your help its much appreciated!!!
10. ### Primitive Polynomials

brilliant thank you. how do i show that these elements that i have generated are the actual elements though? or is it enough just to say they are? and the fact that I havent got the same result twice from 0 to 7 means that it is primitive? thanks so much
11. ### Primitive Polynomials

Homework Statement Hi, I need to show that \alpha+1=[x] is a primitive element of GF(9)= \mathbb{Z}_3[x]/<x^{2}+x+2> I have already worked out that the function in the < > is irreducible but I do not know where to go from this. Homework Equations there are 8 elements in the...
12. ### Proving Isomorphisms

thanks so muchhh i think i know what im doing now!! cant believe never knew that way of writing skew-symmetric matrices
13. ### Proving Isomorphisms

also how can i write a skew-symmetric matrix as a linear combination of I J and K? please help thanks
14. ### Proving Isomorphisms

Homework Statement Hello, I have been asked to prove that three different matrices which are skew-symmetric with a defined operation can be shown to be isomorphic to the usual vectors in 3d space with the operation of the cross product. Homework Equations Well the operation i guess is...
15. ### Number Theory: Matrix Exponential

thanks again. when multiplying matrices to say get M17 what order would i do the matrices in? For example does M17 = M x (M16) or M17 = (M16) x M