A point moves along $$y=x^2+3x.$$ At an instant when $x=2$, its $x$-coordinate is decreasin

Question

A point moves along $$y=x^2+3x.$$ At an instant when $x=2$, its $x$-coordinate is decreasing at $0.4$ units per second. Find the rate of change of its $y$-coordinate, stating whether it is increasing or decreasing.

Accepted Answer

$\frac{\mathrm{d}y}{\mathrm{d}t}=-2.8$ units/s; $y$ decreases at $2.8$ units/s.

Differentiation

Differentiation