Math Broken in python ? :)

just, why the math is broken there ?
not havy but i need to understand why…

from Rhino.Geometry import Vector3d
from Rhino.Geometry import Point3d
from math import pi
from math import cos
from math import sin
Vect1 = Vector3d(10,0,0)
Vect2 = Vector3d(0,10,0)
Vect3 = Vect1 + Vect2
a = 45.0
b = (Vector3d.VectorAngle(Vect1,Vect3)*360)/(2*pi)
c = a-b
print "a=",a,"b=",b,"b-a=",c,"<--- any ideas why it's not 0 ?"
#------------------ futher more...
print (cos(pi/4))-(sin(pi/4)) # not equal to 0
print (cos(pi/4)+1)-(sin(pi/4)+1) # equal to 0

Floating point math fuzz… You’re pretty close to 0 there at e-13 or e-16…

ok i was confused about the scientific notation
every thing take place :innocent:
thx again.