Question

find the direction of u=-3i+8j. i haven't asked a question on here before so lets see how this goes haha

Answer 1

`\bf u=-3i+8j\implies u=\ \textless \ \stackrel{a}{-3}~~,~~\stackrel{b}{8}\ \textgreater \ ~~ \begin{cases} tan(\theta )=(b)/(a)\\\\ \measuredangle \theta =tan^(-1)\left( (b)/(a) \right) \end{cases} \\\\\\ \measuredangle \theta =tan^(-1)\left(-(8)/(3) \right)\implies \measuredangle \theta \approx -69.44^o`

however, the x-coordinate is negative and the y-coordinate is positive, meaning the IV quadrant, namely 180° - 69°, or ≈ 111°.

Answer 2

The direction is about NNW if "i" represents East and "j" represents North.

It would be helpful for you to explain what you intend by "direction."