Re: Trigonometric Problem, Particularly tan() Function
Re: Trigonometric Problem, Particularly tan() Function
- Subject: Re: Trigonometric Problem, Particularly tan() Function
- From: Patrick Walker <email@hidden>
- Date: Sun, 13 Jul 2008 10:30:27 -0300
I can't post the whole thing because it's sort of large and
"integrated" but here is what I have originally done.
float radians;
radians = ([entryField floatValue] * M_PI / 180);
[outField setFloatValue:tan(radians)];
A simple solution could involve using another trigonometgric
implementation available to Xcode. The question is are there any
other than the numerical method "math.h" versions? That's not so bad
because I can simply trap +- 90 and +-270 angles but I am trying to
get as much speed.
My other problems seems to be -2877334 itself. To me, that appears to
be a rather strange value for a floating point number, esp. when
cos(pi/2) is returning near-zero (an "e-08") number as well.
Thanks for the replies.
On 13-Jul-08, at 2:06 AM, Jens Alfke wrote:
On 12 Jul '08, at 9:43 PM, Patrick Walker wrote:
Everthing appears to be fine when going from 0 to 45 degrees but at
90 degrees, the tangent returns -22877334.
That's not what I get. I just compiled and ran:
printf("tan(90) = %g\n", tan(M_PI/2));
which printed:
tan(90) = 1.63312e+16
Which is not infinity, but close enough, given that π/2 can't be
represented precisely in floating-point arithmetic.
I think you need to show us the code you're using, as there seems to
be something wrong with it.
—Jens
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