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Discuss the continuity of f on its domain, where f(x) ,for,for=|x+1|,for -3≤x≤2=|x-5|,for 2<x≤7.

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Question

Discuss the continuity of f on its domain, where f(x) `{:(= |x + 1|",", "for"  -3 ≤ x ≤ 2),(= |x - 5|",", "for"  2 < x ≤ 7):}`.

Sum
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Solution

The domain of f is [– 3, 7].

∵ |x + a| is continuous for all x ∈ R,

We need to consider the continuity of f only at x = 2

f(x) = |x + 1|, for – 3 ≤ x ≤ 2

∴ f(2) = |2 + 1|

= 3

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

= |2 + 1|

= 3

Also, f(x) = |x – 5|, for 2 < x ≤ 7

 ∴ `lim_(x -> 2^+) f(x) =  lim_(x -> 2) |x - 5|`

= |2 – 5|

= 3

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

∴ f is continuous at x = 2.

Hence, f is continuous on its domain [– 3, 7].

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Chapter 8: Continuity - EXERCISE 8.1 [Page 174]

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