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Spherical Hankel Function Calculator

Enter the order n and argument x to compute the spherical Hankel functions h(1)n(x)=jn+i yn and h(2)n(x)=jn−i yn as complex numbers, along with the magnitude and the spherical Bessel components.

Input

Enter the order n and real argument x to compute the spherical Hankel functions h(1)n(x)=jn+i yn and h(2)n(x)=jn−i yn as complex numbers.

Enter a non-negative integer.

Enter a nonzero real number.

Result

h(1) at order 0, x = 3

0.0470400027 + 0.3299974989i

h(2) at order 0

0.0470400027 − 0.3299974989i

Magnitude |h(1) order 0|

0.3333333333

Component breakdown

QuantityValue
Spherical Bessel j order 00.0470400027
Spherical Neumann y order 00.3299974989
Real part of h(1)0.0470400027
Imaginary part of h(1)0.3299974989
Real part of h(2)0.0470400027
Imaginary part of h(2)-0.3299974989

Curves of j order 0 and y order 0

j order 0

y order 0

How it works

  • The spherical Hankel functions are complex functions built from the spherical Bessel function jn(x) and the spherical Neumann function yn(x): the first kind h(1)n(x)=jn(x)+i yn(x) and the second kind h(2)n(x)=jn(x)−i yn(x).
  • The spherical Bessel function jn(x) starts from j0(x)=sin(x)/x and j1(x)=sin(x)/x^2−cos(x)/x. It uses upward recurrence when x is larger than the order and the backward Miller recurrence when x is small, for numerical stability.
  • The spherical Neumann function yn(x) starts from y0(x)=−cos(x)/x and y1(x)=−cos(x)/x^2−sin(x)/x and is evaluated with the always-stable upward recurrence y(n+1)=(2n+1)/x times yn minus y(n−1).
  • h(1)n and h(2)n are complex conjugates of each other, so their magnitudes are equal: |h(1)n(x)|=|h(2)n(x)|=sqrt(jn(x)^2+yn(x)^2).
  • Because yn(x) diverges as x approaches 0, x=0 is not allowed. The order n must be a non-negative integer.

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