WAEC - Further Mathematics (2024 - No. 14)
If r = i + 2j and n = -i + 3j, find |2n - r|.
3.6
4.0
5.0
8.5
توضيح
Given that, r = i + 2j and n = -i + 3j, to find |2n - r|
2n = 2(- i + 3j) = - 2i + 6j
2n - r = [- 2i + 6j] - [ i + 2j] = -3i + 4j
|2n - r| = |-3i + 4j| = \(\sqrt{(-3)^2 + 4^2}\) = \(\sqrt{9 + 16}\) = \(\sqrt{25}\) = 5.0