trigonometry.py 文件源码

def cosox2(x):      
    '''(1-cos(x))/(x*x)'''
    if (abs(x) > 1e-2):         
        return (1. - math.cos(x)) / (x*x)       
    else:           
        return 0.5 - x*x / 24 + x*x*x*x / 720.