Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Help with piecewise functions?

Here is the problem I am having difficulty with:

s(x) = { k^2 + x if x=<(equal or less than) k, x^2 + k if x > k

Show that s(x) is a continuous function for every value of k E R (K is and element of the real numbers)

Thanks in advance!

1 Answer

Relevance
  • 8 years ago
    Favorite Answer

    To show if a function is continuous, you must show that:

    limit as x → a of f(x) = f(a)

    Obviously, s(x) is continuous for x < k and x > k since k^2 + x and x^2 + k are everywhere-continuous polynomials. All that's required to check is when x = k.

    The limit:

    limit as x → k of f(x)

    exists when both left and right side limits agree.

    Right side: limit as x → k+ of f(x) = k^2 + k [here, we substitute x = k into x^2 + k]

    Left side: limit as x → k- of f(x) = k^2 + k [here, we substitute x = k into k^2 + x]

    Since left and right side limits are the same, the function is continuous.

    Hope this helps!

Still have questions? Get your answers by asking now.