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maths help pls

i am so stuck on this question
i've done questions like this before but it would say with limits

---Moved to Maths---
(edited 7 years ago)
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I am talking about B NOT A
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@RDKGames
Original post by mervin101


The trapezium rule says that ∫abf(x).dx≈h2[y0+yn+2(y1+y2+...+yn−1)]\displaystyle \int_a^b f(x) .dx \approx \frac{h}{2}[y_0+y_n + 2(y_1+y_2+...+y_{n-1})] where h=b−anh=\frac{b-a}{n} and nn is the amount of strips.

With this question, it is asking you to use the table to compute the approximation and you can see that h=0.5h=0.5 here.

Then y1=f(x1)=f(1)y_1=f(x_1)=f(1)

and y2=f(x2)=f(1.5)y_2=f(x_2)=f(1.5)

and so on...

What is confusing?
(edited 7 years ago)
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Original post by RDKGames
The trapezium rule says that ∫abf(x).dx≈h2[y0+yn+2(y1+y2+...+yn−1)]\displaystyle \int_a^b f(x) .dx \approx \frac{h}{2}[y_0+y_n + 2(y_1+y_2+...+y_{n-1})] where h=b−anh=\frac{b-a}{n} and nn is the amount of strips.

With this question, it is asking you to use the table to compute the approximation and you can see that h=0.5h=0.5 here.

Then y1=f(x1)=f(1)y_1=f(x_1)=f(1)

and y2=f(x2)=f(1.5)y_2=f(x_2)=f(1.5)

and so on...

What is confusing?


what is n?
i dont know how h = 0.5
4-1/ n
Original post by mervin101
what is n?
i dont know how h = 0.5
4-1/ n


hh is the strip width, so the fixed change in xx. Which is 0.5. Just look at the x-values from the table, they all change by 0.5 as you count on.
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Original post by RDKGames
hh is the strip width, so the fixed change in xx. Which is 0.5. Just look at the x-values from the table, they all change by 0.5 as you count on.


h= b-a divided by n

b-a = 3 (4-1) now i divide by n to get h

i'm still confused about n
i understand h is the strip width

do i rearrange or am i missing something
Original post by mervin101
h= b-a divided by n

b-a = 3 (4-1) now i divide by n to get h

i'm still confused about n
i understand h is the strip width

do i rearrange or am i missing something


You don't need to find nn. You only need it to find hh in these types of questions but you have hh from the get-go...
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Original post by RDKGames
You don't need to find nn. You only need it to find hh in these types of questions but you have hh from the get-go...


can you use this formula?

width of strip/2 x 1st height + sum of middle heights + last height?
Original post by mervin101
can you use this formula?

width of strip/2 x 1st height + sum of middle heights + last height?


No because it's not quite the same as

(half the strip width) multiplied by (1st height + last height + 2 lots of the sum of the middle heights)

if you want the formula in words.
(edited 7 years ago)

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