Question Details

If f(x) = x² sin1x, where x ≠ 0, then the value of the function f(x) at x = 0, so that the function is continuous at x = 0 is

Options

A

0

B

1

C

-1

D

None of these

Correct Answer :

0

Solution :

The correct option is 0.

To find the value of the function f(x) at x=0 so that the function is continuous at x=0, we must apply the definition of continuity.

A function f(x) is continuous at x=0 if and only if the limit of the function as x approaches 0 exists and is equal to the value of the function at x=0.
Mathematically, this condition is written as:

limx0 f ( x ) = f ( 0 )

We are given that for x0, the function is defined as:

f ( x ) = x2 sin 1x

Let us evaluate the limit of f(x) as x approaches 0:

L = limx0 x2 sin 1x

To evaluate this limit, we can use the Sandwich Theorem (or Squeeze Theorem). We know that the sine function is bounded between -1 and 1 for all real numbers. Thus, for any x0:

-1 sin 1x 1

Since x2>0 for all x0, multiplying the entire inequality by x2 preserves the inequality signs:

- x2 x2 sin 1x x2

Now, we take the limit of the outer functions as x approaches 0:
Left limit:

limx0 ( - x2 ) = - (0)2 = 0

Right limit:

limx0 ( x2 ) = (0)2 = 0

By the Sandwich Theorem, since the limits of both bounding functions as x0 are equal to 0, the limit of the middle function must also be 0:

limx0 x2 sin 1x = 0

Therefore, for the function f(x) to be continuous at x=0, we must define:

f ( 0 ) = limx0 f ( x ) = 0

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