Question 1: Is it possible (and reasonable) to have the error function, erf, return 0 for "erf(0)"? Currently it returns the expression: erf(0)
Question 2 (related): The standard normal (or Gaussian) curve has half its (unit) area to the left (and right) of x==0 as we see here... sage: gaussian = 1/sqrt(2*pi)*exp( -(1/2)*x^2 ) sage: integrate( gaussian, x, -oo, 0) 1/2 To find the value of t for which the area is 1/2 we might try sage: solve( integrate(gaussian, x, -oo, t)==1/2, t ) Unfortunately we get the expression [erf(1/2*sqrt(2)*t) == 0] which for t==0 reduces to erf(0) which ideally would reduce to 0 hence Question 1 above ;-) I suppose Question 2 is: Although the erf doco suggests this is all done with PARI, is it possible for [erf(1/2*sqrt(2)*t) == 0] to be made to reduce to [t==0]? -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
