python弧度值转角度值,Python：将弧度转换为度

In the python.org math library, I could only find math.cos(x), with cos/sin/tan/acos/asin/atan. This returns the answer in radians. How can I get the answer in degrees?

Here's my code:

import math

x = math.cos(1)

y = x * 180 / math.pi

print y

30.9570417874

My calculator, on deg, gives me:

cos(1)

0.9998476...

解决方案

Python includes two functions in the math package; radians converts degrees to radians, and degrees converts radians to degrees.

To match the output of your calculator you need:

>>> math.cos(math.radians(1))

0.9998476951563913

Note that all of the trig functions convert between an angle and the ratio of two sides of a triangle. cos, sin, and tan take an angle in radians as input and return the ratio; acos, asin, and atan take a ratio as input and return an angle in radians. You only convert the angles, never the ratios.