Function pvon

recipes/Python/580806_How_Create_PDF_Caustic/recipe-580806.py:21–22

(a)

"""
def pvon(a):                 # starting point of one sun ray
    return(math.cos(a), math.sin(a))

def pbis(a):                 # end point of one sun ray
    return(math.cos(3*a - math.pi), (math.sin(3*a - math.pi)))