Question

Find the direction angle of the vector u=-8i+5j. That is, find the angle between 0 degrees and 360 degrees that u makes with the positive x-axis

Answer 1

we have the vector

u=-8i+5j

see the attached figure to better understand the problem

tan(x)=5/8

x=tan^-1(5/8)

x=32 degrees

Find out the angle theta

148 degrees

the answer is 148 degrees