Trigonometric functions (PR#7728)
On Wed, 16 Mar 2005, Peter Kleiweg wrote:
Thomas Lumley schreef op de 15e dag van de lentemaand van het jaar 2005:
x<-sqrt(2) asin(x^2-1) result in: NaN
Because you can't take the arcsin of 2^2-1=3.
Wrong answer.
You're right. It's actually because you can't take the arcsin of 1+4.4e-16. Same problem, just less extreme.
x<-sqrt(2) x^2-1==1
[1] FALSE
x^2-1>1
[1] TRUE
x^2-1-1
[1] 4.440892e-16 -thomas