# Search results

1. ### Roots of a cubic equation

Many many thanks for your replies, I think I will try and have a go at studying the things you mentioned in your first post for definate! Anything that will expand my knowledge and help me at University can only be a good thing! I managed to get the answer by creating a linear and quadratic...
2. ### Roots of a cubic equation

I've been looking at some practise exams for the University I would like to apply to, I have to sit the exam on 4th November. We have never done finding the roots of a cubic equation before and I cannot figure it out from looking on the internet, the formulas are all horrible to understand...
3. ### Derivative of a sum of functions, also cubic graph roots

Thanks alot for that, didn't realise that was it, glad they are something easy & not hard. I will do a bit of digging on the cubic then and try to work it out ;)
4. ### Derivative of a sum of functions, also cubic graph roots

Derivative of a sum of functions What would you interperate this as? It is one of the subsections of Differentiation from the syllabus of a University entrance Exam in November but I cannot think what it is refering to. Differentiation: Derivative of xa, including for fractional...
5. ### RSA Algorithm Help

I think you are right but I am getting fractions when the modulus function is introduced as I'm unsure how it works. James
6. ### RSA Algorithm Help

Can anyone help with this? Will ask my math/physics teacher tomorrow but wouldnt mind having another go at it first. Cheers James
7. ### RSA Algorithm Help

I'm not sure. Thats where I think I have gone wrong though. Think I messed up at kj = 1 (mod z) 7j = 1 (mod 8) trying to work out the private key as I have tried to teach myself how to do this from an example on a website without really knowing how to do it. James
8. ### RSA Algorithm Help

Struggling to put a number through this as I keep getting my original number as the encrypted number too. A = 11 p = 3 q = 5 n = pq = 15 z = (p-1)(q-1) = 2*4 = 8 k = co-prime of z = 7 So, A=11 n=15 z=8 (Public key) k=7(Public key) kj = 1 (mod z) 7j = 1 (mod 8) for which I am getting j =...
9. ### Maths Behind Credit Card Transactions

I'm having a go at the RSA at the moment, just sticking some values through it to see if I can get it to work. I will try & check out Schneier's books too. Just wondering if anyone knows, when you first introduce (mod x) into it, does the remainder (R) have to be a set amount? eg, I have 13*j...
10. ### Maths Behind Credit Card Transactions

Not that I know of, never heard it mentioned anyway. This is what I am doing... http://www.ocr.org.uk/Data/publications/key_documents/L_GCE_Maths_Spec.pdf [Broken] On page 4, I have done 5.1, 5.2 & 5.16 Currently studying - 5.3 And going on to do 5.4, 5.5, 5.6, 5.7 & 5.8 next year if it...
11. ### Maths Behind Credit Card Transactions

I will have a quick scan over the elliptical curves, do you know anywhere online where I can read up on some of the number theory theorems as I have ne knowlage of it as of yet. Cheers james
12. ### Maths Behind Credit Card Transactions

Thank you for the reply, just looked at those authors, quite expensive books so will ask my local libery to get some copies, or request anyway! Just looked up RSA & I presume you mean the algorithm. Looks fairly complicated but I try going over it tonight & see if I can make sense of what is...
13. ### Maths Behind Credit Card Transactions

I am doing a qualification which requires me to chooses a subject for which I will research & produce a presentation & a 5000 word essay in December. As I plan to study maths at Degree Level I have decided to do a maths based project. My two basic ideas are.... How does Maths keep our...