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Question 23:
Find the points of discontinuity of f, where

The given function f is
It is evident that f is defined at all points of the real line.
Let c be a real number.
Case I:

Therefore, f is continuous at all points x, such that x < 0
Case II:

Therefore, f is continuous at all points x, such that x > 0
Case III:
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The left hand limit of f at x = 0 is,
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The right hand limit of f at x = 0 is,

Therefore, f is continuous at x = 0
From the above observations, it can be concluded that f is continuous at all points of the real line.
Thus, f has no point of discontinuity.