Question

Find the direction angle of the vector u = -3i+8j. That is, find the angle between 0 and 360° that u makes with the positive x-axis (measured counterclockwise)Do not round any intermediate computations, and round your answer to the nearest whole number.

Answer 1

we have the vector

u=-3i+8j

see the attached figure, to better understand the problem

we have that

tan(x)=8/3

x=tan^-1(8/3)

x=69.44 degrees

Find out the angle theta

theta=180-x

theta=180-69.44

theta=111 degrees