Neco Model Questions Vol1 2019 Mathematics Question 23

Practice objective / multiple choice question 23 from the 2019 Neco Model Questions Vol1 Mathematics examination.

Neco Model Questions Vol1 2019 Mathematics Objective / Multiple Choice Hard Difficulty
Question 23 NECO_MODEL_QUESTIONS_VOL1 • 2019 • MATHEMATICS • objective

In a plane, vectors \(\mathbf{a}\) and \(\mathbf{b}\) satisfy \(|\mathbf{a}| = 5\), \(|\mathbf{b}| = 7\) and the angle between them is \(60^{\circ}\). Let \(\mathbf{c} = 2\mathbf{a} - 3\mathbf{b}\). Find the scalar \(k\) such that the vector \(\mathbf{d} = \mathbf{a} + k\mathbf{b}\) is perpendicular to \(\mathbf{c}\), and then compute the magnitude \(|\mathbf{d}|\) (give the magnitude to two decimal places).

Answer Options

A. k = -1\/224, |d| ≈ 5.10
B. k = -5\/448, |d| ≈ 4.50
C. k = -5\/112, |d| ≈ 5.00
Correct Answer D. k = -5/224, |d| ≈ 4.92
Correct Answer
D
Correct Option:
k = -5/224, |d| ≈ 4.92

About This Question

This is Neco Model Questions Vol1 2019 Mathematics Question 23. It is one of the objective questions from the 2019 Neco Model Questions Vol1 Mathematics examination.

Difficulty level: Hard .

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