I have these Cross and Dot Product functions, but I am terrible at math and algebra and cant tell if they are right or not LOL
Note that in the project I will use these functions, I dont have access to Vector from mathutils or any linar algebra package, I have to do it myself.
Pls Heelp 
def dot_product(a, b):
return a.x * b.x + a.y * b.y + a.z * b.z
def cross_product(a, b):
o = vec()
o.x = a.y * b.z - a.z * b.y
o.y = a.z * b.x - a.x * b.z
o.z = a.x * b.y - a.y * b.x
return o