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# C2 have I done this correctly? watch

1. (Original post by junayd1998)
When I plugged it into my calculator, the integral came out to be 5.83 (3sf) so thats close enough seeing that the trepezium rule is meant to be inaccurate as it is an estimate. You near definitely did it correctly.
2. (Original post by Foodatastic)
When I plugged it into my calculator, the integral came out to be 5.83 (3sf) so thats close enough seeing that the trepezium rule is meant to be inaccurate as it is an estimate. You near definitely did it correctly.
but surely the estimate would be the same as mine?? because I used the widths going up in 0.5. idk im kinda confused now have i done it right.
3. (Original post by junayd1998)
Can you explain the line under the diagram? Which formula have you used?
4. (Original post by Muttley79)
Can you explain the line under the diagram? Which formula have you used?
I have used the trapezium rule/ formula
5. (Original post by junayd1998)
I have used the trapezium rule/ formula
I don't think you have used it correctly?

Where is the doubling of the middle 'edges'?
6. (Original post by Muttley79)
I don't think you have used it correctly?

Where is the doubling of the middle 'edges'?
idkkk :/

I thought you use the formula like this so you do the width x 1/2 then 2 + first height all of the sum of the middle heights and then add the last one.
7. (Original post by junayd1998)
idkkk :/

I thought you use the formula like this so you do the width x 1/2 then 2 + first height all of the sum of the middle heights and then add the last one.
that is the correct formula for the trapezium rule method
8. (Original post by junayd1998)
idkkk :/

I thought you use the formula like this so you do the width x 1/2 then 2 + first height all of the sum of the middle heights and then add the last one.
Indeed what is written in script is correct but that is not what you've done - check your substitution.
9. (Original post by the bear)
that is the correct formula for the trapezium rule method
so then have i done it correctly? When i plugged my numbers into that trapeizum rule with the same brackets and everything i got that and iv checked the mark scheme and it says 5.899
10. (Original post by the bear)
that is the correct formula for the trapezium rule method
His text plus the working above does not agree with this correct fomula though ...
11. (Original post by Muttley79)
Indeed what is written in script is correct but that is not what you've done - check your substitution.
I know what I have done ohhh it should be 1.732 +2 rather than 2+1.732 i got it now thanks everyone
12. i cannot see the image in the first post
13. (Original post by junayd1998)
so then have i done it correctly? When i plugged my numbers into that trapeizum rule with the same brackets and everything i got that and iv checked the mark scheme and it says 5.899
That's not what you got before though - your substitution [which you've now deleted] was incorrect.
14. (Original post by the bear)
i cannot see the image in the first post
He's deleted it but found his error ....
15. (Original post by Muttley79)
That's not what you got before though - your substitution [which you've now deleted] was incorrect.
I havent deleted anything. The picture still shows. TSR must have some issues then. Anyways I have seen where I have gone wrong. Thank you for your help
16. (Original post by junayd1998)
but surely the estimate would be the same as mine?? because I used the widths going up in 0.5. idk im kinda confused now have i done it right.
My calculator can do integrals accurately. I didn't use your estimate, I plugged in the equation and the bounds and it told me an accurate answer.

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