Recent content by crazyformath2

Can someone help me. How would I expand (a^n)-1 and is there a theorem for this? an-1

(a^n)-1

Can someone help me. How would you expand or factor out an-1 Is there a theorem for this?

It was a problem for linear algebra class. Dick yea, so M(b) = a matrices of 1/4 entries right?

shouldnt that 5/2 x be negative though? does that make a difference?

I have to find the power series f(x)= 3 / (2 -5x). I devided everything by 2 so I have (1/2) / (1 - 5x/2) = \sum ar^n and then through some steps I have 15x^n / 2^n+1 and I on the right track? How do I find the interval of convergence?

yeaaa...!

so M(b) would be a matrix of all a/4 right?? and then M(a) * M(b) = M(1/2)

i know i don't work it out like a normal matrix right?

if b = 1/2

nevermind i really am an idiot with these matrices, when i multipy a matrices of all a's but a matrice of all b's, i get ab+ab in each entry. and when i do the opposite, i'll get the same answer, but i just don't understand how i'd get back to a.

wouldnt "a" have to be all one's?

I am so lost. I understand what Dick said to a point. I know the determinant cannot be 0 for then there would not be an inverse, correct? but if all the entries are the same won't the determinate be zero?

The problem is: Let K = a 2x2matrix where a is a real number and does not equal zero. That is, all 2x2 in which each entry is the same. Show that is a group under multiplication. And find its identity element. Verify. Please note: That the basic idenity matrix is not the identity element...