Python's Trigonmetric Function Return Unexpected Values

import math print 'python calculator' print 'calc or eval' while 0 == 0: check = raw_input() #(experimental evaluation or traditional calculator) if check == 'eval':

Solution 1:

You don't want o convert the return value of sin() to degrees -- the return value isn't an angle. You instead want to convert the argument to radians, since math.sin() expects radians:

>>> math.sin(math.radians(90))
1.0

Solution 2:

Python's sin and cos take radians not degrees. You can convert using the math.radians function. Basically, you are using the wrong units.

Solution 3:

Most math functions, including Python's math functions, use radians as the measure for trigonometric routines.

Compare:

>>>math.sin(90)
0.8939966636005579
>>>math.sin(3.1415926535)
8.979318433952318e-11
>>>math.cos(180)
-0.5984600690578581
>>>math.cos(2*3.1415926535)
1.0
>>>

Solution 4:

You are using degrees, but the sin function expects radians (see the documentation: help(math.sin)). 90° is 𝜋/2.

>>> import math
>>> math.sin(math.pi/2)
1.0
>>> math.radians(90) - math.pi/20.0

Solution 5:

Convert your input from degrees to radians before calling math.sin