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OCR core 2 maths help for tomorrow - trigonometry question 7 Watch

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    Hey guys, I was doing this paper which is the June 2012 one, and am having a problem with question 7, all parts. I worked out all of the answers fine, but my calculator doesn't give them in fraction form? It only gives them in decimal form? And on the mark scheme, it won't let you give in decimal form even though it's exactly the same. I've never had to use trig in this way before, do i just have to not use my calculator for this question?

    The paper: http://www.ocr.org.uk/Images/136129-...hematics-2.pdf
    The markscheme: http://www.ocr.org.uk/Images/135286-...ics-2-june.pdf

    Cheers for any help
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    (Original post by Majeue)
    Hey guys, I was doing this paper which is the June 2012 one, and am having a problem with question 7, all parts. I worked out all of the answers fine, but my calculator doesn't give them in fraction form? It only gives them in decimal form? And on the mark scheme, it won't let you give in decimal form even though it's exactly the same. I've never had to use trig in this way before, do i just have to not use my calculator for this question?

    The paper: http://www.ocr.org.uk/Images/136129-...hematics-2.pdf
    The markscheme: http://www.ocr.org.uk/Images/135286-...ics-2-june.pdf

    Cheers for any help
    there must be a setting/button on your calculator to turn it from fractions to decimals and back?
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    (Original post by Majeue)
    Hey guys, I was doing this paper which is the June 2012 one, and am having a problem with question 7, all parts. I worked out all of the answers fine, but my calculator doesn't give them in fraction form? It only gives them in decimal form? And on the mark scheme, it won't let you give in decimal form even though it's exactly the same. I've never had to use trig in this way before, do i just have to not use my calculator for this question?

    The paper: http://www.ocr.org.uk/Images/136129-...hematics-2.pdf
    The markscheme: http://www.ocr.org.uk/Images/135286-...ics-2-june.pdf

    Cheers for any help
    I literally just did this with my friends, if you look at the mark scheme it says :"isw if decimal equiv subsequently given.
    Answer only gets full credit."
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    Forgive me if I'm wrong, but can't you just use the information given and draw a triangle, giving the answer

    E.g given tan alpha = 2/5, you can draw a triangle with opposite 2, adjacent 5 and hypotenuse of root[5^2+2^2], so root 29.

    Then using cos, you find adjacent / hypotenuse. So you just get cos alpha = 5 / root 29?
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    For part one, what method are you using?

    Draw out a triangle, label the adjacent, opposite and hypotenuse, and their sizes.
    Work out the hypotenuse, using Pythagoras. You get root 29.

    Tan=opposite/adjacent
    Cos=adjacent/hypotenuse
    So cosx=5/root29

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    (Original post by PKMN TRN JAM)
    I literally just did this with my friends, if you look at the mark scheme it says :"isw if decimal equiv subsequently given.
    Answer only gets full credit."
    Oh alright didn't notice that, thankyou
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    Bank of Pigs is indeed correct. Remember SOHCAHTOA. Tan = O / A, Cos = A / H. You're given two values, so you just have to find Cos (x)
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    I genuinely don't understand why you're having problems with writing it in exact surd form?...hmm.

    Posted from TSR Mobile
 
 
 
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