Question

Find |AB| if A=(1,-4) and B=(-2,7). Also, how would I find the direction of AB?

Answer 1

|AB|=sqrt ((1+2)^2+(-4-7)^2) = sqrt 130

Answer 2

Thank you! Also do you know how to find the direction?

Answer 3

also vector AB = vector B - vector A= (-2-1)i +(7+4)j=-3i + 11j
so unit vector along AB =vector AB /|AB| =-3i/sqrt 130 + 11j/ sqrt 130

Answer 4

Isn't AB (1--2),(-4-7), so it would be <3,-11> or 3i-11j?

Answer 5

if A and B are points; then B-A is the direction of the vector FROM A to B

Answer 6

(..) tends to mean points

<...> tends to indicate vecotrs

but thats not a universal notation

Answer 7

Thank you

Answer 8

youre welcome