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Difference between revisions of "Math bits"

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(Created page with "== modular function in LibreCAD == the standard glibc fmod(x, a) is not convenient here, since we need a modular function work the same way for both positive and negative numb...")
 
(modular function in LibreCAD)
Line 3: Line 3:
  
 
remainder(x - 0.5*a,a)+0.5*a
 
remainder(x - 0.5*a,a)+0.5*a
 +
 +
 +
<math>
 +
  \operatorname{erfc}(x) =
 +
  \frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt =
 +
  \frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}
 +
</math>

Revision as of 16:26, 22 April 2012

modular function in LibreCAD

the standard glibc fmod(x, a) is not convenient here, since we need a modular function work the same way for both positive and negative numbers, instead, we use,

remainder(x - 0.5*a,a)+0.5*a



  \operatorname{erfc}(x) =
  \frac{2}{\sqrt{\pi}} \int_x^{\infty} e^{-t^2}\,dt =
  \frac{e^{-x^2}}{x\sqrt{\pi}}\sum_{n=0}^\infty (-1)^n \frac{(2n)!}{n!(2x)^{2n}}