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If f(x) = {{:((|x+2|)/(tan^(-1)(x+2)), x...

If `f(x) = {{:((|x+2|)/(tan^(-1)(x+2)), x ne -2),(2, x =-2):}`,

A

continuous at x = - 2

B

not continuous at x = - 2

C

differentiable at x = - 2

D

continuous but not differentiable at x = - 2.

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The correct Answer is:
To solve the problem, we need to determine the continuity of the function defined as: \[ f(x) = \begin{cases} \frac{|x+2|}{\tan^{-1}(x+2)} & \text{if } x \neq -2 \\ 2 & \text{if } x = -2 \end{cases} \] ### Step 1: Analyze the function at \( x = -2 \) To check the continuity of \( f(x) \) at \( x = -2 \), we need to evaluate the left-hand limit and the right-hand limit as \( x \) approaches \(-2\). ### Step 2: Calculate the Left-Hand Limit The left-hand limit as \( x \) approaches \(-2\) is given by: \[ \lim_{h \to 0^-} f(-2 + h) = \lim_{h \to 0^-} \frac{|(-2 + h) + 2|}{\tan^{-1}((-2 + h) + 2)} \] This simplifies to: \[ \lim_{h \to 0^-} \frac{|h|}{\tan^{-1}(h)} \] Since \( h \) is approaching \( 0 \) from the left, \( |h| = -h \). Thus, we have: \[ \lim_{h \to 0^-} \frac{-h}{\tan^{-1}(h)} \] Using the fact that \(\lim_{h \to 0} \frac{h}{\tan^{-1}(h)} = 1\), we get: \[ \lim_{h \to 0^-} \frac{-h}{\tan^{-1}(h)} = -1 \] ### Step 3: Calculate the Right-Hand Limit Now, we calculate the right-hand limit as \( x \) approaches \(-2\): \[ \lim_{h \to 0^+} f(-2 + h) = \lim_{h \to 0^+} \frac{|(-2 + h) + 2|}{\tan^{-1}((-2 + h) + 2)} \] This simplifies to: \[ \lim_{h \to 0^+} \frac{h}{\tan^{-1}(h)} \] Again, using the limit property, we have: \[ \lim_{h \to 0^+} \frac{h}{\tan^{-1}(h)} = 1 \] ### Step 4: Compare the Limits and the Function Value Now we compare the left-hand limit, right-hand limit, and the value of the function at \( x = -2 \): - Left-hand limit: \( -1 \) - Right-hand limit: \( 1 \) - \( f(-2) = 2 \) Since the left-hand limit does not equal the right-hand limit, we conclude that: \[ \text{Left-hand limit} \neq \text{Right-hand limit} \] ### Conclusion Since the left-hand limit and right-hand limit are not equal, the function \( f(x) \) is not continuous at \( x = -2 \). Therefore, it is also not differentiable at that point. ### Final Result The function \( f(x) \) is **not continuous** and **not differentiable** at \( x = -2 \). ---
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ML KHANNA-LIMITS, CONTINUITY AND DIFFERENTIABILITY -PROBLEM SET (2) (MULTIPLE CHOICE QUESTIONS)
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  2. Let [ ] denote the greatest integer function and f(x) = [tan^(2)x] The...

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  3. If f(x) = {{:((|x+2|)/(tan^(-1)(x+2)), x ne -2),(2, x =-2):},

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  4. If f(x) = {{:( 3x ^(2) + 12 x - 1",", - 1 le x le 2), (37- x",", 2 lt...

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  5. The set of all points, where the function f(x) =x/(1+|x|) is differen...

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  6. The set of points where the function f(x) = x |x| is differentiable i...

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  7. Prove that the function If f(x)={:{((x)/(1+e^(1//x)) ", " x ne 0),(" ...

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  8. The set of allpoints of differentiability of the function f(x) ={{:(x^...

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  9. At the point x = 1, the function: f(x) = {{:(x^(3)-1, 1 lt x lt inft...

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  10. Let f(x) = "min" {1, x^(2), x^(3)}, then:

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  11. The function f(x) is defined as: f(x) =1/3 -x, x ,lt 1/3 =(1/3-x)^...

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  12. If f(x)={{:(,x^(2)sin((1)/(x)),x ne 0),(,0, x=0):}, then

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  13. Let g(x)=xf(x), where f(x)={{:(x^(2)sin.(1)/(x),":",x ne0),(0,":",x=0)...

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  14. Let f(x)={{:(0,x lt 0),(x^(2),xge0):}, then for all values of x

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  15. Let [x] denotes the greatest integer less than or equal to x. If f(x) ...

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  16. The function f (x) = 1+ |sin x| is

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  17. If f(x)={{:(,(x log cos x)/(log(1+x^(2))),x ne 0),(,0,x=0):} then

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  18. If x+4|y| = 6y then y as a function of x is

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  19. If f'(x(0)) exists, then lim(h to 0)([f(x(0) +h) -f(x(0) -h))/(2h)) is...

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  20. The function f(x) = {{:(|2x-3|[x], x ge 1),(sin((pix)/2), x lt 1):}

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