Results are out! Find what you need...fast. Get quick advice or join the chat
Hey there Sign in to join this conversationNew here? Join for free

Trapezium Rule C2 AQA

Announcements Posted on
Applying to Uni? Let Universities come to you. Click here to get your perfect place 20-10-2014
    • Thread Starter
    • 0 followers
    Offline

    ReputationRep:
    This should be simple but I can't get to the right answer.

    Q) Using the trapezium rule with 3 ordinates, find an estimate for the area under the curve y = x^2 - 3x from x = 4 to x = 8.

    If there are 3 ordinates, you do 4 (8-4) divided by 3 right? I think that's where I'm going wrong. Then input 4+1.333 and the answer of that + 1.333 as my middle ordinates then x=4 and x=8 as my end points, so I get:

    4 + 2(12.44 + 24.44) + 40 giving me 117... the answer is apparently 80.
    • 9 followers
    Offline

    ReputationRep:
    you need to do with x = 4,6,8 which would mean that h=2

    then you use the trapezium rule with those values.
    • Thread Starter
    • 0 followers
    Offline

    ReputationRep:
    Doing so, I still only get 24. Where am I going wrong?
    • 9 followers
    Offline

    ReputationRep:
    did you use this formulae:

    \frac{h}{2}(y_0+y_n+2(y_1))

    where h = difference in the x values = 2
    y0 = y value at x = 4
    y1 = y value at x = 6
    yn = y value at x = 8

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. By joining you agree to our Ts and Cs, privacy policy and site rules

  2. Slide to join now Processing…

Updated: April 19, 2012
New on TSR
Article updates
Reputation gems:
You get these gems as you gain rep from other members for making good contributions and giving helpful advice.