OCR MEI Numerical Methods 12th June 2015

Original post by Genty Boy

No, 3dp.

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but why can't u give ur calculator value?

Reply 43

Genty Boy

3

Original post by runny4

but why can't u give ur calculator value?

The error is 3dp, so your answer is only accurate to 3dp

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Reply 44

Genty Boy

3

Original post by Leechayy

Okay so ignoring the weird structure of these papers, this is what worries me the most:

54, 52, 51, 52, 53, 58, 57, 56, 62, 60, 56, 60, 62, 61, 50, 59, 56, 54 ~ Boundaries for an A in NM from June 2005- June 2014

What are these grade boundaries? Like jumping from 50-59 is pretty ridiculous if you ask me.
I don't get how some papers give boundaries of 62/72 then 50/72 :colonhash:

It'll probably be 62 this year cuz OCR are trolls

I hope so because that would imply an easy test.

Last years paper was dreadful, the last question defeated almost everyone (hence the subsequent part). Just did it and got 57 which is an A but still, way way off what I'm used to getting.

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Reply 45

Original post by Genty Boy

The error is 3dp, so your answer is only accurate to 3dp

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don't you look at sig fig instead of decimal places?

Reply 46

Bruhh

10

What do you guys do when you get a negative error when it asks for the absolute error? In every mark scheme I've seen they use the negative value although surely if it's the absolute error then it would always be positive?

Reply 47

Original post by Bruhh

What do you guys do when you get a negative error when it asks for the absolute error? In every mark scheme I've seen they use the negative value although surely if it's the absolute error then it would always be positive?

'When an exact value x is approximated by X, the absolute error is defined as the modulus of the error.

absolute error = |ε| = |X - x|' So you should take the positive value!

Reply 48

On June 2014 does anyone have any work solutions for 7 (iii) and (iv) I'm major confused. So annoying last years papers is very easy up until the last part!! (60/72 :angry:

)

(edited 8 years ago)

Reply 49

natalie987

Hi could anyone please help with this question?

X is an approximation to the number x such that X = x (1 + r). State what r represents. Show that, provided r is small, Xn ≈ x n (1 + nr).

I know r is relative error and I feel like the other bit is to do with binomial expansion but I dont know how to show this? Its really similar to this past paper question too which I dont know how to do either?

The number X is an approximation to an exact value x, and X = x(1 + r).

(ii) Use the binomial theorem to show that X n ≈ xn(1 + nr) provided r is small.

Thanks :smile:

Reply 50

Genty Boy

3

Original post by natalie987

Hi could anyone please help with this question?

X is an approximation to the number x such that X = x (1 + r). State what r represents. Show that, provided r is small, Xn ≈ x n (1 + nr).

I know r is relative error and I feel like the other bit is to do with binomial expansion but I dont know how to show this? Its really similar to this past paper question too which I dont know how to do either?

The number X is an approximation to an exact value x, and X = x(1 + r).

(ii) Use the binomial theorem to show that X n ≈ xn(1 + nr) provided r is small.

Thanks :smile:

You need to do a binomial expansion of (1+r)^n. This will give 1+ (n)(r)+...
So X^n=x^n(1+nr)

Hope that helps

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Reply 51

I was wondering if anyone could help me on part (ii)

Answers for part (i)

-> h=0.4 3.195
-> h=0.2 2.974
-> h=0.1 2.871

Reply 52

lizard54142

Original post by Keys10

I was wondering if anyone could help me on part (ii)

Answers for part (i)

-> h=0.4 3.195
-> h=0.2 2.974
-> h=0.1 2.871

Consider the differences between the successive estimates, and their ratio.

Reply 53

for june 2013 7v, why can't u give 61.80114905 as ur answer?

Reply 54

Original post by lizard54142

Consider the differences between the successive estimates, and their ratio.

What do you mean by ratio ???

Reply 55

Original post by lizard54142

Consider the differences between the successive estimates, and their ratio.

for june 2013 7v, why can't u give 61.80114905 as ur answer?

Reply 56