CUET Preparation Today
The function $f(x)=x^3-3x$ is : |
Increasing in (0, ∞) and decreasing in (-∞, 0) Decreasing in (0, ∞) and increasing in (-∞, 0) Decreasing in (-∞,-1] ∪ [1, ∞) and increasing in (-1, 1) Increasing in (-∞, -1] ∪ [1,∞) and decreasing in (-1, 1) |
Increasing in (-∞, -1] ∪ [1,∞) and decreasing in (-1, 1) |
The correct answer is Option (4) → Increasing in $(-∞, -1] ∪ [1,∞)$ and decreasing in $(-1, 1)$ $f(x)=x^3-3x$ $f'(x)=3x^2-3=0⇒x=1,-1$ using wavy curve method
f(x) is increasing in $(-∞,-1]∪[1,∞)$ decreasing in $(-1, 1)$ |
