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)

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)

anonymous · Answer

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

anonymous · Answer

My calculator thinks it's about -13 degrees.

anonymous · Answer

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