Strange results from trigonometric functions

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1

hello,
I use trigonometric functions “tan” and “cos” in my code. The result of AMPL is strange, as shown below.

thet tan(the) cos(the)

30.97 -0.48 0.90
23.96 -2.35 0.39
33.69 -1.17 -0.65 …

Can you please explain why this happens?

2

Are 30.97, 23.96, and 33.69 expressed in degrees? AMPL’s trigonometric functions require their arguments to be in radians. To convert, you need to replace the by the*(2*pi/360).

To get an accurate value for \pi in AMPL, you can define param pi = 4*atan(1);.