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Examine whether the function is continuous at the points indicated against them : f(x) =x3-2x+1, if x≤2=3x-2, if x>2} at x = 2

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Question

Examine whether the function is continuous at the points indicated against them:

f(x)  `{:(= x^3 - 2x + 1",",  "if"  x ≤ 2),(= 3x - 2",",  "if"  x > 2):}}` at x = 2

Sum
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Solution

`lim_(x -> 2^-) "f"(x) = lim_(x -> 2^-) (x^3 - 2x + 1)`

= (2)3 – 2(2) + 1

= 5

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

= 3(2) – 2

= 4

∴ `lim_(x -> 2^-) "f"(x) ≠ lim_(x -> 2^+) "f"(x)`

∴ f(x) is discontinuous at x = 2

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Chapter 8: Continuity - EXERCISE 8.1 [Page 172]

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