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3 votes
3 answers
310 views

Closed form for infinite sum involving Chebyshev polynomials

There exists a generating function for the Chebyshev polynomials in the following form: $$\sum\limits_{n=1}^{\infty}T_{n}(x) \frac{t^n}{n} = \ln\left( \frac{1}{\sqrt{ 1 - 2tx + t^2 }}\right)$$ ...
edrezen's user avatar
  • 243
0 votes
1 answer
165 views

Reference for the exponential generating function for the Chebyshev polynomials of the second kind?

Does anyone have a reference for the exponential generating function for the Chebyshev polynomials of the second kind? $$ \sum_{n=0}^{\infty}\frac{t^n U_n(x)}{n!}= etc $$ I know what it is from the ...
James McLaughlin's user avatar
0 votes
1 answer
43 views

Can we define the generating function for all $x$ and all $t$

The Chebyshev polynomials of second kind are defined for any $x \in \Bbb R$ (or even $x \in \Bbb C$), e.g. via the recurrence relation $$ U_0(x) = 1 \\ U_1(x) = 2x \\ U_{n+1}(x) = 2x U_n(x) - U_{...
Safwane's user avatar
  • 3,854
2 votes
3 answers
1k views

Derive the Rodrigues' formula for Chebyshev Polynomials

Rodrigues' formula for Chebyshev Polynomials is stated as $$T_n(x)=(-1)^n2^n\frac{n!}{(2n)!}\sqrt{1-x^2}\frac{d^n}{dx^n}(1-x^2)^{n-1/2}$$ I understand how the Rodrigues formula for all other special ...
Sooraj S's user avatar
  • 7,674
0 votes
1 answer
170 views

Show that first order Chebyshev polynomials are in fact polynomials

Given the 1st order Chebyshev polynomials $$ G(x,t) = \sum_{n=0}^{+\infty} T_n(x) t^n = \frac{1-tx}{1-2xt+t^2} $$ I'm wondering how can I show that $T_n(x)$ are polynomials ?
Mathieu's user avatar
  • 607
2 votes
1 answer
185 views

Relationship between Poisson's integral formula and the generating function of Chebyshev polynomials

On the disk $\{z:|z|<R\}$, Poisson's integral formula is $$u(r,\theta)=\frac1{2\pi}\int_0^{2\pi}\frac{(R^2-r^2)f(\phi)}{R^2-2Rr\cos(\theta-\phi)+r^2}\,d\phi$$ which solves the Dirichlet problem. ...
TheSimpliFire's user avatar
  • 27.1k
1 vote
2 answers
3k views

Derive recurrence relation for Chebyshev polynomials from generating function

Hej, I have a question about the following problem: Derive a recurrence formula for $m \ge 0$ given the generating function formula $$ \frac{1}{1-2xt+t^{2}}=\sum_{m=0}^\infty U_m(x)t^{m}. $$ What I ...
Vollkaracho's user avatar
8 votes
1 answer
702 views

How to get from Chebyshev to Ihara?

I have competing answers on my question about "Returning Paths on Cubic Graphs Without Backtracking". Assuming Chris is right the following should work. Up to one thing: The number of returning paths ...
draks ...'s user avatar
  • 18.6k