Crazy Trigonometry

Hi! I’m having some trouble with the trigonometric functions in Flash. I haven’t learned too much about trig, but I’ve got some problems.

I put in this code:
and I got the result of:
Shouldn’t it be 1?

I also tried the cosine and sine of 45, and I got two numbers that their sums would exceed 1, like .8 and .5, about.

What is wrong with Flash’s trigonometry? Is there some way that I need to use a degree-mode-type trigonometric functions rather than radians?

Thanks for your help.