A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

Meehan98

  • one year ago

Identify a counterexample to disprove n3 ≤ 3n^2, where n is a real number. n = 2 n = −1 n = 0 n = 0.5

  • This Question is Closed
  1. Meehan98
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    It's supposed to be n^3 < or equal to 3n^2.

  2. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    just put the 4 values into the inequality only one of them gives an incorrect result - but that proves the inequality is not true for all real numbers, as required

  3. Meehan98
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I did that and I got; 8<12=true -1<3=true 0=0=true .25<.75=false

  4. Meehan98
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    So, it would be 0.5 but that's incorrect.

  5. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    0.5 ^3 is not 0.25

  6. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    however 0.125 <=0.75 so I believe 0.5 IS the correct answer

  7. Meehan98
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay, the computer must be incorrect then.

  8. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    hold on a minute tho sorry...

  9. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    0.5^3 =.125 so the inequality IS true but it is also true for all the other answers

  10. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    if x>3 then the inequality is false - but that is not an option did oyu type the question correctly?

  11. Meehan98
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    This is a screenshot of the exact problem, and the red arrow means that's the answer I picked and it was incorrect.

    1 Attachment
  12. MrNood
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah - as I corrected myself - ALL the answers seem to give a correct solution to the inequality - so none is a 'counterexample' any value x>3 IS a counterexample

  13. Meehan98
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    hmm.. okay. Thank you.

  14. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.