ocr MEI NM exam 18/05/11

yeh i used the best estimate as the middle value, i got 5 iterations including the starting value, but i stated this, not sure if the starting value is an iteration or not?,

when working out the quadratic to the last question did anyone get like ... -1.25 and 33 point somthing and then when doing the cubic got -3 point somthing and 17 point somthing? Because i wasn't sure about the -3 because the values either side were 1 and -1 so -3 seemed unlikely however i quickley sketched a cubic and it did seem reasonable and i checked it and seemed right? Anyone got thoughts?

I'm not feeling great. I'm hoping for a decent B, and that I'll be able to drag it up with FP1 and D1.
I got -1.25 for f(2) and like 33 for f(8) on the initial bit, for whoever said that.

Linear interpolation went straight over my head, so I just guessed.
Anyone get 8.3 recurring for the the last part of 3.

Also, how does the derivative show whether or not it diverges?! God damn not having a proper teacher!

If |f'(x)| < 1 then there will be convergence

Otherwise, for fixed point iteration, there will be divergence.

So all you had to do was write that f'(x) was -4x^3 and then show that for any points in the interval [0.7,0.8] the f'(x) < -1