Q191 / 270 · NDA 2017 (Phase 2) · Mathematics
The points $(\mathrm{a}, \mathrm{b}),(0,0),(-a,-b)$ and $\left(a b, b^2\right)$ are
- Athe vertices of a parallelogram
- Bthe vertices of a rectangle
- Cthe vertices of a square
- Correct answerDcollinear
Solution
Given points, $\mathrm{A}(\mathrm{a}, \mathrm{b}), \mathrm{B}(0,0), \mathrm{C}(-\mathrm{a},-\mathrm{b}), \mathrm{D}\left(\mathrm{ab}, \mathrm{b}^2\right)$.
Slope of $A B=\frac{b-0}{a-0}=\frac{b}{a}$
Slope of $B C=\frac{b}{a}$
Slope of $A C=\frac{b}{a}$
Slope of $B D=\frac{b}{a}$.
So, the points are collinear
Hence, the correct answer is option: 'D'.