Part 1 Flashcards
Vectors are called parallel or collinear if
u=av or v=bu
Commutativity of vector addition
u+v=v+u
associativity of vector addition
(u+v)+w=u+(v+w)
additive identity
There is a vector 0 (- Rn such that v+0=v
Opposite vector
there is a vector−v ∈ n such that v + (−v) = 0;
Distributivity of vector addition
a(u + v) = au + av;
Distributivity of scalar addition
(a + b)v = av + bv;
Homogeneity of multiplication by scalar
(a·b)v = a(bv);
Unitarity of multiplication by scalar
1v=v
dot(inner or scalar) product
u•v=x1y1+x2y2
Vectors are orthogonal or perpendicular
If the dot product is 0
symmetry
u•v=v•u
Homogeneity
(au)•v = a(u•v)
Distributivity
(u + v)•w = u•w + v •w
Positiveness
v •v ≥0, and v•v = 0 if and only if v=
0.
norm or vector length
|v|= (v•v)^1/2
normalised vector or unit vector
|v|=1
Cauchy-Schwarz inequality
|u•v|≤|u|·|v|
Triangle inequality
|u + v|≤|u|+ |v|
Pythagoras Theorem
|u + v|^2 = |u|^2 + |v|^2
The angle between between vectors
cos(ϕ) = u•v/|u||v|.
proju (v)
(u•v)u/(u•u)
The projection of v on u
vector can be presented using the fixed vectors d and p:
v = p + td
parametric form of the line l
x = p1 + td1
y = p2 + td2