- Exam
- JEE Main
- Year
- 2021
- Date
- 22 July
- Shift
- Morning Shift
- Subject
- Mathematics
- Chapter
- Continuity and Differentiability
JEE Main 2021 · 22 July · Morning Shift · Mathematics · Continuity and Differentiability
Let f: R → R be a function defined as f(x) = \ cases 3(1 - (| x...
Let be a function defined as f\left(x\right) = \left\{\begin{cases}3\left(1 - \dfrac{| x |}{2}\right) & \text{if} & | x | \le 2 \\ 0 & \text{if} & | x | > 2\end{cases}\right .
Let be given by If and denote the number of points in where is not continuous and not differentiable, respectively, then is equal to ________.
Correct answer
0
Step-by-step solution
The given function is f\left(x\right) = \left\{\begin{cases}3\left(1 - \dfrac{| x |}{2}\right) & if & | x | \le 2 \\ 0 & if & | x | > 2\end{cases}\right)</p><p>By using the definition of modulus function, we have\left|x\right| = \left\{\right) and also, we know that if \left|x\right| > a, ⇒ x a,⇒ f\left(x\right) = \left\{\right)
Now, f\left(x - 2\right) = \left\{\begin{cases}3\left(1 + \dfrac{x - 2}{2}\right), & - 2 \le x - 2 \le 0 \\ 3\left(1 - \dfrac{x - 2}{2}\right), & 0 x - 2orx - 2 > 2\end{cases}\right)</p><p>⇒ f\left(x - 2\right) = \left\{\right)
And, f\left(x + 2\right) = \left\{\begin{cases}3\left(1 + \dfrac{x + 2}{2}\right), & - 2 \le x + 2 \le 0 \\ 3\left(1 - \dfrac{x + 2}{2}\right), & 0 x + 2orx + 2 > 2\end{cases}\right)</p><p>⇒ f\left(x + 2\right) = \left\{\right)
Hence, g\left(x\right) = f\left(x + 2\right) - f\left(x - 2\right) = \left\{\right)</p><p>The graph ofg is given below
From the graph we can observe that the function \left(x\right)g is not continuos is and the graph has sharp corners at the points \left(- 4, 0\right), \left(4, 0\right), \left(- 2, 3\right) \text{ and } \left(2, - 3\right)g is not differentiable are