WAEC - Further Mathematics (2008 - No. 35)
Find the value of the constant k for which \(a = 4 i - k j\) and \(b = 3 i + 8 j\) are perpendicular.
\(\frac{2}{3}\)
2
3
\(\frac{3}{2}\)
ব্যাখ্যা
For perpendicular vectors, their dot product = 0.
\((4i - kj). (3i + 8j) = 12 - 8k = 0\)
\(8k = 12 \implies k = \frac{3}{2}\)