A particle moves along the curve $y=x^2+2 x$. Then, the point on the curve such that $x$ and $y$ coordinates…
- $(1,3)$
- $\left(\frac{1}{2}, \frac{5}{2}\right)$
- $\left(-\frac{1}{2},-\frac{3}{4}\right)$
- $(-1,-1)$
Solution

Given equation of curve is $ y=x^2+2 x $ On differentiating both sides w.r.t. $t$, we get $ \frac{d y}{d t}=(2 x+2) \frac{d x}{d t} $

$ \begin{aligned} \Rightarrow & & 2 x & =-1 \\ \Rightarrow & & x & =-1 / 2, y=-3 / 4 \end{aligned} $ $\therefore$ Point on the curve is $\left(-\frac{1}{2},-\frac{3}{4}\right)$
Asked in: AP EAMCET 2004
Practice more Applications of Derivatives questions on Aicharya