CUET Preparation Today
Points at which normal to the curve $y=x^3-3 x$ is parallel to y-axis are: |
(1, 2) and (1, -2) (1, -2) and (-1, 2) (1, 2) and (-1, -2) (-1, 2) and (1, 2) |
(1, -2) and (-1, 2) |
The correct answer is Option (2) → (1, -2) and (-1, 2) Slope of the tangent line, $\frac{dy}{dx}=\frac{d}{dx}(x^3-3x)=3x^2-3$ $⇒3x^2-3=0$ $⇒x=±1$ $y=(1)^3-3(1)=1-3=-2$ $y=(-1)^3-3(-1)=2$ $⇒(1, -2)$ and $(-1, 2)$ |
