WAEC - Further Mathematics (2008 - No. 30)
Express \(r = (12, 210°)\) in the form \(a i + b j\).
\(6(-i + \sqrt{3} j)\)
\(6(-\sqrt{3} i - j)\)
\(6(i - \sqrt{3} j)\)
\(6(i + \sqrt{3} j)\)
คำอธิบาย
\(F = F \cos \theta i + F \sin \theta j\)
\(r = (12, 210°) = 12 \cos 210 i + 12 \sin 210 j\)
= \(- 6\sqrt{3} i - 6j\)
= \(6(-\sqrt{3} i - j)\)