Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Mathematical Induction

  1. Oct 17, 2006 #1
    ok I am really confused now topic says it all..

    I am given 4n-3 = n(2n-1)

    using mathemadical induction proof that is true.

    P(1) both equal 1

    P(k) 4k-3 = k(2k-1)
    = k^2 - k

    P(k+1) 4(k+1)-3 =(k+1)(2(k+1)-1)

    if i simplify it all i get that
    4k +1=2k^2 +3k +1

    but stick at that point.

    any help plz.
     
  2. jcsd
  3. Oct 17, 2006 #2

    quasar987

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The proposition 4n-3 = n(2n-1) for all natural numbers is false; no wonder you can't prove it. Take n=5 for exemple. It would then say that 17=45
     
  4. Oct 17, 2006 #3
    hmm....did u miss out the summation sign on the left side?
     
  5. Oct 17, 2006 #4
    kay here is the exact question from the text.

    1+5+9+....+(4n-3)=n(2n-1)

    so how do i do this then...
     
  6. Oct 17, 2006 #5
    You do realise that it's not the same as what you said in the first post?

    Assuming it's true for some k, add 4(k+1)-3 to the left and try to simplify it so that you get the corresponding term for k+1 on the right.
     
  7. Oct 17, 2006 #6
    (4n-3) is not summation (4n-3) :rofl: sub n=k+1 on the right and proof that its equal to k(2k-1) + (k+1)th term. i guess it should be alrite from here :biggrin:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Mathematical Induction
  1. Mathematical induction (Replies: 24)

  2. Mathematical Induction (Replies: 3)

  3. Mathematical Induction (Replies: 15)

  4. Mathematical induction (Replies: 0)

Loading...