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Discuss the continuity of the following function at the point or on the interval indicated against them. If the function is discontinuous, identify the type of discontinuity and state whether - Mathematics and Statistics

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Question

Discuss the continuity of the following function at the point or on the interval indicated against them. If the function is discontinuous, identify the type of discontinuity and state whether the discontinuity is removable. If it has a removable discontinuity, redefine the function so that it becomes continuous:

f(x) `{:(= x^2 + 2x + 5"," , "for"  x ≤ 3),( = x^3 - 2x^2 - 5",", "for"  x > 3):}`

Sum

Solution

`lim_(x -> 3^-) "f"(x) = lim_(x -> 3^-) (x^2 + 2x + 5)`

= (3)2 + 2(3) + 5

= 9 + 6 + 5

= 20

`lim_(x -> 3^+) "f"(x) = lim_(x -> 3^+) (x^3 - 2x^2 - 5)`

= (3)3 + 2(3)2 – 5

= 27 – 18 – 5

= 4

∴ `lim_(x -> 3^-) "f"(x) ≠ lim_(x -> 3^+) "f"(x)`

∴ `lim_(x -> 3) "f"(x)` does not exist

∴ f(x) is discontinuous at x = 3

This continuity is irremovable.

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Continuous and Discontinuous Functions
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Chapter 8: Continuity - MISCELLANEOUS EXERCISE-8 [Page 177]

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