Difference between revisions of "Spherical Bessel j"

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(Properties)
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=Properties=
 
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{{:Relationship between spherical Bessel j sub nu and sine}}
<strong>Theorem:</strong> The following formula holds for non-negative integers $n$:
 
$$j_n(z)=(-1)^nz^n \left( \dfrac{1}{z} \dfrac{d}{dz} \right)^n \left( \dfrac{\sin z}{z} \right).$$
 
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<strong>Proof:</strong> █
 
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Revision as of 06:38, 10 June 2015

The spherical Bessel function of the first kind is defined by $$j_{\nu}(z)=\sqrt{\dfrac{\pi}{2z}}J_{\nu + \frac{1}{2}}(z),$$ where $J_{\nu}$ denotes the Bessel function of the first kind.

Properties

Theorem

The following formula holds for non-negative integers $n$: $$j_n(z)=(-1)^nz^n \left( \dfrac{1}{z} \dfrac{\mathrm{d}}{\mathrm{d}z} \right)^n \left( \dfrac{\sin z}{z} \right),$$ where $j_n$ denotes the spherical Bessel function of the first kind and $\sin$ denotes the sine function.

Proof

References

Proposition: The following formula holds: $$1=\displaystyle\sum_{k=0}^{\infty} (2k+1)j_k(z)^2.$$

Proof:

Proposition: The following formula holds: $$\dfrac{\sin(2z)}{2z} = \displaystyle\sum_{k=0}^{\infty} (-1)^k(2k+1)j_k(z)^2.$$

Proof:

<center>Bessel functions
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