Engineering
Mathematics
Types of Discontinuities
Question

Let [t] denote the greatest integer ≤t  and  limx→0x[4x]=A  Then the function, f(x) = [x2] sin(πx) is discontinuous, when x is equal to :

A+1

A+5

A+21

A

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Solution

limx→0x(4x−{4x})=A⇒limx→04−x{4x}=A⇒4−0=A

check when

(A) x=A+1⇒x=5⇒discontinuous

(B) x=A+21⇒x=5⇒continuous

(C) x=A⇒x=2⇒continuous

(D) x=A+5⇒x=3⇒continuous