Question

Find the magnitude and direction angle θ of the following vectors. Round the magnitude to the nearest tenth, and round the direction angle to the nearest degree, if rounding is necessary.

u = (9, -2)

Answer 1

\[\theta = \tan^{-1} \frac{-2}{9}\]Use a calculator to find the value. Note that theta will be negative.

Answer 2

My calculator thinks it's about -13 degrees.

Answer 3

Magnitude of the vector is by Pythagorean Theorem. I reckon it's sqrt 85, pretty close to 9.2.