# Find which of the functions is continuous or discontinuous at the indicated points: at x = 4

Given, …(1)

We need to check its continuity at x = 4

A function f(x) is said to be continuous at x = c if,

Left hand limit(LHL at x = c) = Right hand limit(RHL at x = c) = f(c).

Mathematically we can represent it as- Where h is a very small number very close to 0 (h0)

Now according to above theory-

f(x) is continuous at x = 4 if - Clearly,

LHL = {using equation 1}

LHL = h > 0 as defined above.

|-h| = h

LHL = LHL = -1/2 …(2)

Similarly, we proceed for RHL-

RHL = {using equation 1}

RHL = h > 0 as defined above.

|h| = h

RHL = RHL = 1/2 …(3)

And,

f(4) = 0 {using eqn 1} …(4)

Clearly from equation 2 , 3 and 4 we can say that f(x) is discontinuous at x = 4

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