Find the magnitude and direction of the vector \(p = (5i - 12j)\)

  • A (13, 113.38°)
  • B (13, 067.38°)
  • C (13, 025.38°)
  • D (13, 157.38°)
waec 2017furthermathematics

The correct answer is D. (13, 157.38°)

\(p = (5i - 12j); |p| = \sqrt{5^{2} + (-12)^{2}}\)

= \(\sqrt{169} = 13\)

\(\tan\theta = \frac{-12}{5} = -2.4 \implies \theta = -67.38°\)

Direction = \(90° - (-67.38°) = 157.38°\)

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