Vectors Flashcards
1
Q
Scalar dot product
A
a.b = |a||b|cosx
a.b = 0 if a and b are perp
2
Q
Vector line equation
A
r_ = a_ + sigma b_
3
Q
Cartesian line equations
A
lambda = (x-a1)/b1, etc for y and z increasing numbers
4
Q
Vector intersections between two lines
A
Check if parallel.
If not parallel, check if intersecting by simultaneous equations.
If not, they are skew
5
Q
How to prove dot product angle thing
A
Triangle with vectors then cosine rule
6
Q
Cross product formula
A
(A2B3 - A3B2) +
(A3B1 - A1B3) +
(A1B2 - A2B1)
7
Q
Angle between two vectors formula
A
cosx = (a.b)/|A||B|
