1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Binomial expansion

  1. Oct 26, 2009 #1
    1. The problem statement, all variables and given/known data
    Determine the coefficient of p4q7 in the expansion of (2p-q)(p+q)10


    2. Relevant equations



    3. The attempt at a solution
    sry, i cant attempt to solve this coz i dont even know how to expand this using formula
     
  2. jcsd
  3. Oct 26, 2009 #2

    rock.freak667

    User Avatar
    Homework Helper

    Do you know how to expand (a+b)n using the binomial expansion?
     
  4. Oct 26, 2009 #3
    well i know
    but does this related to (a+b)n
     
  5. Oct 26, 2009 #4
    extremely required help
     
  6. Oct 26, 2009 #5

    rock.freak667

    User Avatar
    Homework Helper

    because you can expand out (p+q)10 and you can multiply out the terms which will give you p4q7
     
  7. Oct 26, 2009 #6

    lanedance

    User Avatar
    Homework Helper

    might help, to see what rockfreak is implying, if you write it as
    (2p)(p+q)10 - q(p+q)10

    now think about which terms you need to look at for p4q7
     
  8. Oct 26, 2009 #7
    well that one is definitely wrong
    because (2p-q)(p+q) is not equal to (2p)(p+q) - q(p+q)
     
  9. Oct 26, 2009 #8
    well no other methods?
    because this method will definitely cause a lot of hardwork:frown:
     
  10. Oct 26, 2009 #9

    lanedance

    User Avatar
    Homework Helper

    really? try multiplying both sides out
     
  11. Oct 26, 2009 #10

    lanedance

    User Avatar
    Homework Helper

    if you use the binomial expansion theorem, this will tell you what the terms are without doing all the multiplication. do you know what the binomial expansion theorem is?

    you just have to decide which terms you want to find - see previous post
     
  12. Oct 26, 2009 #11

    lanedance

    User Avatar
    Homework Helper

  13. Oct 27, 2009 #12
    hay hay hay buddy, chill out
    maybe i doesnt know binomial expansion very well, but you dont have react so....:frown:
    just now i comment you are wrong just because normally the multiplying of two terms are not like that....
    just sorry for offended you
     
  14. Oct 27, 2009 #13

    lanedance

    User Avatar
    Homework Helper

    no offence, just trying to help out
     
  15. Oct 27, 2009 #14
    if you are not offended thats good
    thx for your help
    you and rock.freak667's help is much appreciated
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Binomial expansion
  1. Binomial expansions (Replies: 5)

  2. Binomial expansion (Replies: 1)

  3. Binomial Expansion (Replies: 6)

  4. Binomial expansion (Replies: 14)

  5. Binomial expansion (Replies: 2)

Loading...