# Recent content by pbxed

1. ### Is the group of permutations on the set {123} Cyclic? Justification required

Its not cyclic because no permutation can be a generator for the group. That is, no one permutation when composed with itself however many times can generate all the permutations within the group. Is that correct?
2. ### Is the group of permutations on the set {123} Cyclic? Justification required

Oh okay. I think I was just outleveling myself for a minute. The next part of the question ask if the subgroup of even permutations is cyclic. I guess what I have shown is the proof that it is cyclic. Thanks for your help jbunniii
3. ### Is the group of permutations on the set {123} Cyclic? Justification required

Homework Statement Consider the group of permutation on the set {123}. Is this group cyclic? Justify your answer Homework Equations The Attempt at a Solution I wrote out the cayley table for this group, and noticed that if we take (123)^3 = e . Seeing as we can get back to the...
4. ### Squeeze Theorem - Multivarible question

Okay, So I subbed in x = r cos (alpha) and y = r sin (alpha) and simplified the expression down to 1 + 5r^3(cos(alpha))^2(sin(alpha))^3 My question is, because as the lim r-> 0 then isn't the limit just 1 (which is what I wanted to show) and I wouldn't have to use the squeeze theorem if...
5. ### Squeeze Theorem - Multivarible question

Oh, sorry I did mean the third one. I copied and pasted directly from a pdf file and it messed up the formatting without me realising sorry. Ill try the polar coordinates now thx.
6. ### Squeeze Theorem - Multivarible question

Hi, I'm having a lot of difficulty with finding limits of multivariable functions. A question like this comes up every year in the final exam and it will always ask for use of the squeezing theorem. Homework Statement (a) Suppose that f(x, y) = 1 +(5x2y3)/x2 + y2 for (x, y) =/=...
7. ### Group Theory (Abstract algebra manipulations)

Oh, I just worked it out. God I feel dumb. Thx for your help micromass :)
8. ### Group Theory (Abstract algebra manipulations)

Well c = a*a^-2 c=a^-1 right? Thats the value I got but when I look at the solution its wrong. Supposedly c = b^-2 = a^4
9. ### Group Theory (Abstract algebra manipulations)

Homework Statement Let a,b,c,d be elements of a group G and let ab = c, bc = d, cd = a, da = b. Examine the expression da^2b and first derive an expression for b in powers of a. Then express c and d in powers of a. Show that a^5 = e (identity element) Homework Equations The Attempt...
10. ### Resits exams in the summer.

Hi, By leaving everything to the last minute I managed to flunk all my math courses this year. As such I now have 4 resit exams in August to prepare for. The courses are Introduction to Analysis Sets and Algebraic structures Linear Algebra Advanced Calc (goes up to about Calc II level...
11. ### Second Order Partial Derivatives + Chain Rule

Homework Statement Let z = z (x,y) be a function with x = x(s), y = y(t) satisfying the partial differential equation (Ill write ddz/ddt for the partial derivative of z wrt t and dz/dt for the total derivative of z wrt t, as I have no idea how to use Latex.) ddz/ddt +...
12. ### Convergent Sequences problem

is it rude of me to say that I don't really understand your reply and ask for further clarification, either from yourself on someone else?
13. ### Convergent Sequences problem

Homework Statement Let f: N -> N be a bijective map. for n Є N a sub n = 1 / f(n) Show that the sequence (a sub n) converges to zero. Homework Equations The Attempt at a Solution Basically I have been stuck on this problem for hours now and have read through my notes and...
14. ### Equivalence relations and classes problem.

Homework Statement Let X = {a,b,c,d}. How many different equivalence relations are there on X? What subset of XxX corresponds to the relation whose equivalence classes are {a,c},{b,d} Homework Equations N/A The Attempt at a Solution So I wrote out all the possible "blocks"...