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Engineering function

BESSELK

Returns the modified Bessel function Kn(x).

Rarely usedDifficulty 1600 · ExpertUsage rank #513 of 520
Practice · 2 questions →

When to use it

The modified Bessel function of the second kind, Kn(x).

The shape of it

Syntax
=BESSELK(x, n)

Worked examples

  • Order one

    =BESSELK(1.5,1) 0.277387804

    Order 1 at 1.5.

  • Order zero

    =BESSELK(1,0) 0.421024438

    Order 0 at 1.

  • Larger x

    =BESSELK(2,0) 0.113893873

    Decays quickly.

Worth knowing

  • Infinite at x = 0; x must be positive.
  • Decays exponentially.
  • Order is truncated to an integer.

Where it goes wrong

  • #NUM! for x of 0 or less, or a negative order.
  • #VALUE! for non-numeric input.

Related

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