NDA 2025
- Exam
- NDA
- Year
- 2025
- Subject
- Mathematics
- Chapter
- Continuity and Differentiability
NDA 2025 · Mathematics · Continuity and Differentiability
Consider the following for the two (02) items that follow: Let f(x)...
Consider the following for the two (02) items that follow:
Let \begin{cases} x^3, & x^2 < 1 \\ x^2, & x^2 \geq 1 \end{cases}$x = -1x = 1$.
Which of the statements given above is/are correct?
Let \begin{cases} x^3, & x^2 < 1 \\ x^2, & x^2 \geq 1 \end{cases}$x = -1x = 1$.
Which of the statements given above is/are correct?
Options
- AI only
- BII only
- CBoth I and II
- DNeither I nor II
Correct answer
D. Neither I nor II
Step-by-step solution
The given function can be rewritten as:
\begin{cases} x^2, & x \leq -1 \\ x^3, & -1 < x < 1 \\ x^2, & x \geq 1 \end{cases}$x = -1= \lim_{x \to -1^-} x^2 = (-1)^2 = 1= \lim_{x \to -1^+} x^3 = (-1)^3 = -1f(x)x = -1x = 1x = 1= \lim_{x \to 1^-} x^3 = 1= \lim_{x \to 1^+} x^2 = 1f(1) = 1^2 = 1x = 1x = 1= \lim_{x \to 1^-} \dfrac{d}{dx}(x^3) = \lim_{x \to 1^-} 3x^2 = 3(1)^2 = 3= \lim_{x \to 1^+} \dfrac{d}{dx}(x^2) = \lim_{x \to 1^+} 2x = 2(1) = 2f(x)x = 1$. Statement II is incorrect.
Both statements are incorrect.
Answer: Neither I nor II
\begin{cases} x^2, & x \leq -1 \\ x^3, & -1 < x < 1 \\ x^2, & x \geq 1 \end{cases}$x = -1= \lim_{x \to -1^-} x^2 = (-1)^2 = 1= \lim_{x \to -1^+} x^3 = (-1)^3 = -1f(x)x = -1x = 1x = 1= \lim_{x \to 1^-} x^3 = 1= \lim_{x \to 1^+} x^2 = 1f(1) = 1^2 = 1x = 1x = 1= \lim_{x \to 1^-} \dfrac{d}{dx}(x^3) = \lim_{x \to 1^-} 3x^2 = 3(1)^2 = 3= \lim_{x \to 1^+} \dfrac{d}{dx}(x^2) = \lim_{x \to 1^+} 2x = 2(1) = 2f(x)x = 1$. Statement II is incorrect.
Both statements are incorrect.
Answer: Neither I nor II