SP8 Apr 23 Q2

Discussion in 'SP8' started by barns, Sep 7, 2023.

  1. barns

    barns Made first post

    Hi

    Could someone tell me what the step is from the first equation to the second equation in the examiners report please when trying to get ZB>ZA?

    How did they get from n/(n+391) > sqrt(n)/40 to sqrt(n)/(n+391) > 1/40? Where did the sqrt(n) come from in sqrt(n)/(n+391) > 1/40?

    Thanks
     
    barns, Sep 7, 2023
    #1
  2. Katherine Young

    Katherine Young ActEd Tutor Staff Member

    Just divide both sides by sqrt(n).
     
    Katherine Young, Sep 8, 2023
    #2
  3. barns

    barns Made first post

    Thanks for your reply - Why can we not just do n/(n+391) > 1/40, why do you need to divide both sides by sqrt(n)?
     
    barns, Sep 8, 2023
    #3
  4. Ian Senator

    Ian Senator ActEd Tutor Staff Member

    Hi Barns

    Just basic algebra? Maybe you've not realised that sqrt(n)*sqrt(n)=n. Note your formula in your second post is different from that in your first post.

    Ian
     
    Ian Senator, Sep 8, 2023
    #4

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