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    When it says suitable starting value what do I use? part 3b
    Also for 5ii. The way you work out alpha is saying tan alpha = b/a
    Is b=-1 or 1?
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    your iteration graph sort of resembles a square root graph, but flipped about the y axis.

    Start the iterations at x=1 Convergence is pretty rapid.
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    5 2) eh? alpha is roughly 14 degrees...
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    (Original post by Hasufel)
    5 2) eh? alpha is roughly 14 degrees...
    Yh I got that as well but is it Rcos(x-14)=2 or Rcos(x+14)=2?
    Because when I use the first one I get a different answer from the markscheme
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    2nd one, because when you work out R, R is \sqrt{17}

    and the angle is \arctan(1/4)

    it works out that way because of the minus sign in the expansion:

    R \cos(x+ \alpha) = R \cos(x) \cos(\alpha) - R \sin(x) \sin(\alpha) \equiv 4 \cos(x)- \sin(x)

    cancels itself out when you do the tan thing. (you DO usually pay attention to what quadrant it`s in, and here, it WOULD be in the 4th (180 deg+14.03..) - but the question specifies a range..
 
 
 
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Updated: January 26, 2015
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