AS C2 homework! Radians.

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  1. jessica_anne_clu's Avatar
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    • Location: Leicester
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    AS C2 homework! Radians.
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    I have uploaded a photo of the question If there are any queries about understanding what i've done, please ask.

    I thought that an arc length was θr, but when I converted the 45degrees to pi/4 radians and multiplied it by 10, it gave me the wrong answer.
    If somebody could instruct me how to do it but not tell me the actual answer that'd be great thankyou!
  2. Implication's Avatar
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    Re: AS C2 homework! Radians.
    The length of arc XY is θr, where θ is angle XOY, where O is the centre of the circle. If C were the centre of the circle, then your method would be correct.
    Last edited by Implication; 18-03-2012 at 14:18.
  3. Dr A's Avatar
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    Re: AS C2 homework! Radians.
    (Original post by jessica_anne_clu)
    Click image for larger version. 

Name:	for the student room.JPG 
Views:	19 
Size:	22.8 KB 
ID:	137009

    I have uploaded a photo of the question If there are any queries about understanding what i've done, please ask.

    I thought that an arc length was θr, but when I converted the 45degrees to pi/4 radians and multiplied it by 10, it gave me the wrong answer.
    If somebody could instruct me how to do it but not tell me the actual answer that'd be great thankyou!

    The formula is

    l=\frac {2\pi xr}{2\pi}

    which simplifies to

    l= xr

    where x is the angle in degrees.
    Last edited by Dr A; 18-03-2012 at 14:19.
  4. jessica_anne_clu's Avatar
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    • Location: Leicester
    • Posts: 143
    Re: AS C2 homework! Radians.
    (Original post by Implication)
    The length of arc XY is θr, where θ is angle XOY, where O is the centre of the circle. If C were the centre of the circle, then your method would be correct.
    ok, thankyou! I never think of things like that :P
    If it isn't the centre of the circle, what do I do instead?
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