subexpressions

[Steven D'Aprano]

On Sat, 02 Jun 2007 05:54:51 -0700, Steve Howell wrote:

>> 
>>    def f(x): y = x*x; return sin(y)+cos(y);
>> 
> 
> Although I know valid trigonometry is not the point of
> this exercise, I'm still trying to figure out why
> anybody would ever take the square of an angle. 
> What's the square root of pi/4 radians?

Approximately 0.886 radians. It corresponds to the angle of a point on the
unit circle quite close to (sqrt(2/5), sqrt(3/5)), or if you prefer
decimal approximations, (0.632, 0.775).

Angles are real numbers (in the maths sense), so sqrt(pi/4) radians is
just as reasonable an angle as pi/4 radians. Both are irrational numbers
(that is, can't be written exactly as the ratio of two integers).



-- 
Steven