Find the angle between vectors u and v if u= i + 4j and v= -i+2j. a. 40.60 degrees b. 41.56 degrees c. 39.36 degrees d. 42.01 degrees e. 38.67 degrees
u is in the first quadrant. Angle with pos x axis is atan(4/1)
v is in the second quadrant Angle with pos x axis = 180-atan(2)
angle between them = 180-atan(2)-atan(4)
180-atan(2)-atan(4) = 40.601294645004 40.60 degrees
However I do not understand why there is an i and a j.