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If the following function is continuous at x = 2 then the value of k will be ______. f(x) = ,,,{2x+1,ifx<2 k,ifx=23x-1,ifx>2 - Mathematics

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Question

If the following function is continuous at x = 2 then the value of k will be ______.

f(x) = `{{:(2x + 1",", if x < 2),(                 k",", if x = 2),(3x - 1",", if x > 2):}`

Options

  • 2

  • 3

  • 5

  • – 1

MCQ
Fill in the Blanks

Solution

If the following function is continuous at x = 2 then the value of k will be 5.

f(x) = `{{:(2x + 1",", if x < 2),(                 k",", if x = 2),(3x - 1",", if x > 2):}`

Explanation:

k = 5

∵ f(x) is continuous at x = 2

∴ LHL = RHL = f(2)   ...(i)

Now LHL = `lim_(h -> 0) f(2 - h)`

= `lim_(h -> 0) 2(2 - h) + 1`

= `lim_(h -> 0) 5 - 2h`

= 5 – 0

= 5

RHL = `lim_(h -> 0) f(2 + h)`

= `lim_(h -> 0) 3(2 + h) - 1`

= `lim_(h -> 0) 5 + 3h`

= 5 + 0

= 5

And f(2) = k

Then by (i),

LHL = RHL = f(2)

`\implies` k = 5

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