R: Strange trig function behavior

Question

As a Matlab user transitioning to R, I have ran across the problem of applying trigonometric functions to degrees. In Matlab there are trig functions for both radians and de

Answer 1

This is floating point arithmetic:

> all.equal(cosd(90), 0)
[1] TRUE
> all.equal(cosd(270), 0)
[1] TRUE

If that is what you meant by "does not work properly"?

This is also a FAQ: http://cran.r-project.org/doc/FAQ/R-FAQ.html#Why-doesn_0027t-R-think-these-numbers-are-equal_003f