Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

If K is such that the area of triangle ABC is 3, where A(1, 3), B(0, 0) and C(K, 0), then the value(s) of K is/(are) :

Options:

0

±1

±2

$\frac{3}{2}$

Correct Answer:

±2

Explanation:

The correct answer is Option (3) → ±2

area = $\frac{1}{2}\begin{vmatrix}1&3&1\\0&0&1\\k&0&1\end{vmatrix}=3$

expanding along $R_2$

$\left|\frac{3k}{2}\right|=3⇒|k|=2$

$k=±2$