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    Hi! Could someone take a look at these two questions for me, please?

    They're both from OCR Additional Maths June 2007.

    Q13iii. I worked out the height as 36.3cm using the sine rule but in the mark scheme the height is actually 34.8cm. I'm wondering why I can't use the sine rule to get the same answer? (other than the fact that it's wrong)

    Q14ii: I've done parts 1 and 3 but I don't really understand how to do part 2.
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    (Original post by karmacrunch)
    Hi! Could someone take a look at these two questions for me, please?

    They're both from OCR Additional Maths June 2007.

    Q13iii. I worked out the height as 36.3cm using the sine rule but in the mark scheme the height is actually 34.8cm. I'm wondering why I can't use the sine rule to get the same answer? (other than the fact that it's wrong)

    Q14ii: I've done parts 1 and 3 but I don't really understand how to do part 2.
    Wih Q14ii you're expected to solve the simultaneous equations.

    It could look like this: x^2 - y^2 = (x+0.95)^2 - (y+1.05)^2

    Which you then solve.
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    In Q13(iii), sine rule does work:

    a/sinA = b/sinB

    40/sin90 = h/sin60.5

    Hence h = 40(sin60.5)/sin90 = 34.814... according to my calculator.
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    (Original post by TheOtherSide.)
    Wih Q14ii you're expected to solve the simultaneous equations.

    It could look like this: x^2 - y^2 = (x+0.95)^2 - (y+1.05)^2

    Which you then solve.
    Is that because you can rearrange the equations so Position A is 4=... and Position B is 4=...?

    If so, I get it. Thank you!

    (Original post by OscarTG)
    In Q13(iii), sine rule does work:

    a/sinA = b/sinB

    40/sin90 = h/sin60.5

    Hence h = 40(sin60.5)/sin90 = 34.814... according to my calculator.
    I tried it again and my calculator's giving the same answer now. I must have typed it in wrong... repeatedly. Thank you though!
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    (Original post by karmacrunch)
    Is that because you can rearrange the equations so Position A is 4=... and Position B is 4=...?

    If so, I get it. Thank you!

    Yep. And no problem!
 
 
 
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