python math problem

[Kene Meniru]

I am trying to calculate the coordinates at the end of a line. The length 
and angle of the line are given and I am using the following formula:

x = (math.sin(math.radians(angle)) * length)
y = (math.cos(math.radians(angle)) * length)

The following are sample answers in the format (x, y) to the given 
length/angle values of the line:

120/0  = (0.0, 25.0)
120/89 = (24.9961923789, 0.436310160932)
120/90 = (25.0, 1.53075794228e-15)
120/91 = (24.9961923789, -0.436310160932)

Why am I getting a string number instead of the expected answer  for 120/90 
which should be (25.0, 0.0). This happens at all multiples of 90 (i.e. 180 
and 270)

-- 

Kene
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KeMeniru at gmail.com