[comp.arch] Professional Programmers and cos

rik@june.cs.washington.edu (Rik Littlefield) (12/27/88)

Remember the posting about converting cos(atan(x)) to 1/(1+x*x)?
It touched off quite a chain of postings about what professional 
programmers should and shouldn't be responsible for.  

Well, guys, I'm not sure it was deliberate, but we've been had.  In fact,

  cos(atan(x)) = 1/SQRT(1+x*x)

(Hint: what's the hypotenuse of a right triangle whose sides are 1 and x?)

I hope at least some of you get the same chuckle I did out of this.  I'll
defer comment on the efficiency of the correct substitution to Herman Rubin.

--Rik