- #1
cpt_carrot
- 29
- 4
The Bessel function can be written as a generalised power series:
[tex]
J_m(x) = \sum_{n=0}^\infty \frac{(-1)^n}{ \Gamma(n+1) \Gamma(n+m+1)} ( \frac{x}{2})^{2n+m}
[/tex]
Using this show that:
[tex]
\sqrt{\frac{ \pi x}{2}} J_{1/2}(x)=\sin{x} [/tex]
where
[tex]
\Gamma(p)=\int_{0}^{\infty} x^{p-1}e^{-x}dx
[/tex]
and therefore
[tex] \Gamma(p+1)=p\Gamma(p) [/tex]
Wea re also given that:
[tex] \Gamma(3/2)=\frac{\sqrt{\pi}}{2} [/tex]
My answer so far goes something like:
We are obviously trying to get the series expansion for the Bessel function into the form of the Taylor series for sin:
[tex] \sin{x} = \sum_{n=0}^\infty \frac{(-1)^n x^{2n+1}}{(2n+1)!} [/tex]
Simplyfing the expression for J by replacing m by 1/2 and Gamma(n+1) by n! I ca get reasonably close to the Taylor series but I'm having trouble getting rid of the Gamma(n+3/2)
Any help would be much appreciated!
Also as this is my first post: Hello Everybody
(And I hope the LaTex works :tongue2: )
[tex]
J_m(x) = \sum_{n=0}^\infty \frac{(-1)^n}{ \Gamma(n+1) \Gamma(n+m+1)} ( \frac{x}{2})^{2n+m}
[/tex]
Using this show that:
[tex]
\sqrt{\frac{ \pi x}{2}} J_{1/2}(x)=\sin{x} [/tex]
where
[tex]
\Gamma(p)=\int_{0}^{\infty} x^{p-1}e^{-x}dx
[/tex]
and therefore
[tex] \Gamma(p+1)=p\Gamma(p) [/tex]
Wea re also given that:
[tex] \Gamma(3/2)=\frac{\sqrt{\pi}}{2} [/tex]
My answer so far goes something like:
We are obviously trying to get the series expansion for the Bessel function into the form of the Taylor series for sin:
[tex] \sin{x} = \sum_{n=0}^\infty \frac{(-1)^n x^{2n+1}}{(2n+1)!} [/tex]
Simplyfing the expression for J by replacing m by 1/2 and Gamma(n+1) by n! I ca get reasonably close to the Taylor series but I'm having trouble getting rid of the Gamma(n+3/2)
Any help would be much appreciated!
Also as this is my first post: Hello Everybody
(And I hope the LaTex works :tongue2: )