vectors

This week we learned about vectors, a fairly easy thing to do. Things to know: 1. a vector is a slope 2. to add a vector you use the formula v+u = (a,b)+(c,d)=(a+c,b+d) 3. to subtract a vector you use the formula v-u = (a,b)-(c,d)=(a-c,b-d) 4. scalar multiplication is kv=k(a,b)=(ka,ka) 5. to find a vector from two points you do p2-p1 6. vector equation - (x,y)=(xo,yo)+t(ab) {xo and yo is the point and ab is the vector} 7. parametric equations - x=xo+at y=yo+bt 8. magnitude of a vector - |v|= square root of x^2+y^2 9. component form is (r cos theta, r sin theta) example 1. find a vector equation of the line through A(4,2) and B(3,4) 1. all you have to do is p2-p1 and write it in an equation 2. p2-p1 = -1,2 3. vector equation : (x,y)= (4,2)+t(-1,2) example 2. write example 1 in a parametric equation 1. x= xo+at 2. x= 4-t 3. y= yo+bt 4. y= 2+2t