Question 512 Marks
Determine whether the function $y=12+4x-7x^{2}$ is increasing or decreasing at $x=2$.
Answer
View full question & answer→$\frac{dy}{dx} = 4 - 14x$.
At $x = 2, \frac{dy}{dx} = 4 - 14(2) = 4 - 28 = -24$.
Since $\frac{dy}{dx} < 0$, the function is decreasing at $x = 2$.
At $x = 2, \frac{dy}{dx} = 4 - 14(2) = 4 - 28 = -24$.
Since $\frac{dy}{dx} < 0$, the function is decreasing at $x = 2$.