Math things

how to find angle between lines in 3D

dot product is the easier thingy btw

what is speed in vectors

the modulus of the velocity vector

how to do cross product

| a b |

| c d |

in this scenario, ad - bc for coefficients of i, j, k.

REMEMBER THAT COEFFICIENT OF J IS NEGATIVE

how to find a line that is perpendicular to two lines

its direction vector will be the cross product of the direction vectors of the two lines

dot product of two perpendicular lines direction vectors

will be 0

area of triangle (vectors)

for triangle OAB, where O is common point between A and B

compound angle identity

how to determine odd function

substitute -x into f, and if f(-x) is equal to -f(x), then it’s odd

basically if you rotate the graph 180, then it’ll be the same as before