The components of vector A⃗ are Ax = + 3.90 and Ay = -4.00. What is the angle measured counterclockwise from the +x-axis to vector A⃗ ?

Answer 1

Tan A = Y/X = -4.0/3.90 = -1.02564.
A = -45.7o = 45.7o CW from +x-axis. = 314.3o CCW from +x-axis.