1.) direction vector = velocity
tan(@) = opposite/adjacent = 5/3 = 1.4
tan(@) = 1.4 => @=59 (above horizontal, bearings from vertical implies bearing = 90-@)
bearing = 031
2.) direction vector = (7,-7.5)-(4,-6) => d = (3,-1.5)
tan(@) = opposite/adjacent = -(1.5/3)
tant(@) = -0.5 => @ = 27 (below horizontal, therefore bearing = 90 + @)
bearing = 117
3.) try it yourself, if you cant do, i'll work it out...
generally direction vectors...
(ai + bj) => bearing = 90 - (tan^-1)(b/a)
(ai - bj) => bearing = 90 + (tan^-1)(b/a)
(-ai - bj) => bearing = 270 - (tan^-1)(b/a)
(-ai + bj) => bearing = 270 + (tan^-1)(b/a)