Physics brushup

[Thomas Klemm]

Here's another one:

Code:

   001 { 42 21 11 } f LBL A
   002 {        3 } 3
   003 {       15 } 1/x
   004 {       11 } sqrt(x)
   005 {    43 32 } g RTN

0.5773502692

Short, fast but inaccurate.
But I'm sure you already knew that.