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Find the values of k so that the function f is continuous at the indicated point. at x f(x)={kx +1ifx≤πcosxifx>π at x =π - Mathematics

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Question

Find the values of k so that the function f is continuous at the indicated point.

`f(x) = {(kx +1, if x<= pi),(cos x, if x > pi):} " at  x " = pi`

Sum

Solution

`f(x) = {(kx +1, if x<= pi),(cos x, if x > pi):} " at  x " = pi`

If f(x) is continuous at `x = pi` it implies:

`f(pi) = lim_(x -> pi^+)  f(x) = lim_(x -> pi^-)  f(x)`

`=> k (pi) + 1 = cos (pi) = k (pi) + 1`

`=> k (pi) + 1 = cos (pi)`

`=> k (pi) + 1 = - 1`

`=> k = (-2)/pi`

That is, for the quantity `k = (-2)/pi` this function is continuous at `x = pi`.

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Chapter 5: Continuity and Differentiability - Exercise 5.1 [Page 161]

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NCERT Mathematics [English] Class 12
Chapter 5 Continuity and Differentiability
Exercise 5.1 | Q 28 | Page 161

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