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

The way I would deal with this would be to force asin() to work in 
complex mode:

 > x <- sqrt(2)
 > asin(x^2-1+0i)
[1] 1.570796+2.980232e-08i
 >

(the error is large because the derivative of arcsin is infinite at 
x=1).

--
Robin Hankin
Uncertainty Analyst
Southampton Oceanography Centre
European Way, Southampton SO14 3ZH, UK
  tel  023-8059-7743