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location Antarctica
age 79
visits member for 2 years
seen Oct 16 at 9:51

Self-learning mathematics. Many thanks to those who make time to help others on the site.


Apr
25
revised Show that there is no rational number $r=m/n$ such that $r^3=3$
added 96 characters in body
Apr
25
comment Show that there is no rational number $r=m/n$ such that $r^3=3$
@ThomasAndrews Does it make a difference that this is cubed root?
Apr
25
asked Show that there is no rational number $r=m/n$ such that $r^3=3$
Apr
25
accepted Proving a complex equality
Apr
25
comment Proving a complex equality
So for the trivial case, you can't use the quotient you've set $z$ equal to?
Apr
23
comment Proving a complex equality
I'm aware of that answer, but I'm looking for an algebraic answer simply because that wouldn't come to me immediately. How did you see that it was an ellipse? I ask because it's not in the familiar form that you see in conic sections of calculus.
Apr
23
asked Proving a complex equality
Apr
14
asked Number of matrices giving even row and column sum
Apr
14
accepted Finding a closed form expression for this sum
Apr
13
comment Finding a closed form expression for this sum
How do you know that the 2nd term is equal to $(1/\sqrt{1-4x})^2$?
Apr
13
comment Finding a closed form expression for this sum
@MarcvanLeeuwen How did you search for that? I didn't know how to search for it because there's no specific name or term associated with it. O.w. I'd just have to look through all the results one at a time.
Apr
13
asked Finding a closed form expression for this sum
Apr
11
accepted Solving functional equation for generating function
Apr
11
comment Solving functional equation for generating function
But doesn't that change the value of the sum?
Apr
11
comment Solving functional equation for generating function
Yeah, I've been trying to figure out how to get the indices to start at $0$ all day. Why is it you can just start the the indices (in your hint) at $0$?
Apr
11
asked Solving functional equation for generating function
Apr
11
comment Simplifying Catalan number recurrence relation
@BrianM.Scott In the first half of your answer, how do you go from $1+x\sum_{n\ge 0}\sum_{k=0}^nC_kC_{n-k}x^n$ to $1+x\left(\sum_{n\ge 0}C_nx^n\right)^2$
Apr
10
comment Finding functional equation for generating function
yeah, it's not a big deal. :) I was just sort of stating it as an fyi.
Apr
10
comment Finding functional equation for generating function
your solution doesn't match the solution in the text :[
Apr
10
revised Finding functional equation for generating function
added 100 characters in body