Neco Model Questions Vol1 2025 Mathematics Question 17

Practice objective / multiple choice question 17 from the 2025 Neco Model Questions Vol1 Mathematics examination.

Neco Model Questions Vol1 2025 Mathematics Objective / Multiple Choice Hard Difficulty
Question 17 NECO_MODEL_QUESTIONS_VOL1 • 2025 • MATHEMATICS • objective

In the plane, vectors \(\mathbf{a}\) and \(\mathbf{b}\) satisfy \(|\mathbf{a}| = 5\), \(|\mathbf{b}| = 8\) and the angle between them is \(60^{\circ}\). A third vector \(\mathbf{c}\) is defined by \(\mathbf{c}=\mathbf{a}+k\mathbf{b}\) for some real number \(k\). If the magnitude of \(\mathbf{c}\) equals the area of the parallelogram formed by \(\mathbf{a}\) and \(\mathbf{b}\), find the possible value(s) of \(k\).

Answer Options

A. \frac{-5+15\sqrt{20}}{16}\text{ or }\frac{-5-15\sqrt{20}}{16}
B. \frac{-5+10\sqrt{21}}{16}\text{ or }\frac{-5-10\sqrt{21}}{16}
C. \frac{-5+15\sqrt{21}}{8}\text{ or }\frac{-5-15\sqrt{21}}{8}
Correct Answer D. \frac{-5+15\sqrt{21}}{16}\text{ or }\frac{-5-15\sqrt{21}}{16}
Correct Answer
D
Correct Option:
\frac{-5+15\sqrt{21}}{16}\text{ or }\frac{-5-15\sqrt{21}}{16}

About This Question

This is Neco Model Questions Vol1 2025 Mathematics Question 17. It is one of the objective questions from the 2025 Neco Model Questions Vol1 Mathematics examination.

Difficulty level: Hard .

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Chat with Support