The point at which the tangent to the curve $y=x^2-4 x$ is parallel to x-axis, is
Answer & explanation
Correct answer: option 4
Let $\left(x_1, y_1\right)$ be the required point. Then,
$\left(\frac{d y}{d x}\right)_{\left(x_1, y_1\right)}=0 \Rightarrow 2 x_1-4=0 \Rightarrow x_1=2$
Since $\left(x_1, y_1\right)$ lies on $y=x^2-4 x$.
∴ $y_1=x_1{ }^2-4 x_1 \Rightarrow y_1=4-8=-4$
Hence, the coordinates of the point are (2, -4)