Let f :R→R and g :R→R be respectively given by fx=x+1 and gx=x2+1. Define h :R→R by hx= max⁡fx, gxifx ≤0min⁡fx, gxifx>0 Then number of points at which hx is not differentiable is_________

JEE Advanced · Mathematics · 23. C&D

Let $f : R \to R$ and $g : R \to R$ be respectively given by $f (x) = |x| + 1$ and $g (x) = x^{2} + 1 .$ Define $h : R \to R$ by $h (x) = \{\begin{matrix} \max \{f (x), g (x)\} & i f & x \leq 0 \\ \min \{f (x), g (x)\} & i f & x > 0 \end{matrix}$
Then number of points at which $h (x)$ is not differentiable is_________

Verified Solution

Answer & Solution

Correct Answer

(D) 3

Step-by-step Solution

Detailed explanation

h (x) = \{\begin{matrix} \begin{matrix} x^{2} + 1, & x \in (- \infty, - 1] \\ - x + 1, & x \in [- 1, 0] \\ x^{2} + 1, & x \in [0, 1] \end{matrix} \\ \begin{matrix} x + 1, & x \in [1, \infty) \end{matrix} \end{matrix}

Hence, not differentiable at

x = - 1, 0, 1

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From JEE Advanced

Explore more questions on app

Let f :R→R and g :R→R be respectively given by fx=x+1 and gx=x2+1. Define h :R→R by hx= max⁡fx, gxifx ≤0min⁡fx, gxifx>0Then number of points at which hx is not differentiable is_________

Step-by-step Solution