The area of a triangle with vertices (0,

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Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Applications of Derivatives

Question:

The area of a triangle with vertices (0, -3), (0, 3) and (k, 0) in 27 sq.units. The value of k is :

Options:

-27

-6

-18

-9

Correct Answer:

-9

Explanation:

Points (0, -3), (0, 3), (k, 0)

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

expanding along $C_1$

$Δ =\frac{1}{2}k(-6)=27$

so $k = -9$