Inverse Sin, Cos, Tan

[LB]

Well MMF2 only accepts numbers between 0 and 1, wheras the TI calculators will accept between -1 to 1, eg cos^-1(-1)=pi.

[drnebula]

Again, it would be helpful if you could explain what you are trying to do. Sine, cosine, etc. deal with triangles, so all of the numbers whould always be positive. But in some schemes, negatives are used to indicate which quadrant the triangle is in. You can get the same results in several ways. One is to use angles greater than 90, so that the sine of 30 degrees and 160 (30 + 90) degrees give the same answer, even though they are in different quadrants. Or you can set the calculations to be different whether the angle is between 0 and 90 or between 90 and 180. But it all depends what you are trying to accomplish. Also, since you are getting pi, you have your calculator set to radian mode. I suggest you work in degrees for simplicity, unless your application requires radians.
Steve