Question

Vector v has a direction of (-5,26). Find the direction angle for v.

a. 280.9 degrees
b. 259.1 degrees
c. 100.9 degrees
d. 79.1 degrees

Answer 1

since you are trying to find the direction you have to use

tan theta= y/x

tan theta= 26/-5

theta= tan^-1I26/-5I
theta= 79.11 degrees but since (-5,26) is found in the second quadrant you have to substract 180 - a to obtain the direction angle

theta= 180 -a
=180 - 79.11

theta = 100.88 degrees

vector v has a direction angle of 100.88 degrees