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    This is not a TeeEm thread - I'm genuinely stuck

    The question : AB = AC. Find the value of theta. Ignore the 'b' in the diagram - not relevant to the question.



    A teacher gave this question to one of my tutees, probably not realising how hard it is. The best I've done is get to a quartic but I could've made a mistake and I couldn't solve the quartic directly anyway.

    Help!

    (Please post any solutions in spoilers)
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    no thanks :afraid:
    that is not a fun looking question...

    just had a very brief attempt but got scared off pretty quickly xD
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    What study level is this?
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    (Original post by notnek)
    This is not a TeeEm thread - I'm genuinely stuck

    The question : AB = AC. Find the value of theta.



    A teacher gave this question to one of my tutees, probably not realising how hard it is. The best I've done is get to a quartic but I could've made a mistake and I couldn't solve the quartic directly anyway.

    Help!
    doesn't seem too difficult i'm doing it currently
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    (Original post by thefatone)
    doesn't seem too difficult i'm doing it currently
    I could just be being stupid.
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    (Original post by notnek)
    I could just be being stupid.
    oops i made a mistake xD
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    (Original post by surina16)
    What study level is this?
    The student who was given this question is in Year 13 doing A Level Maths (not further maths).

    I have no idea where the teacher got the question from or if they made it themselves.
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    (Original post by notnek)
    This is not a TeeEm thread - I'm genuinely stuck

    The question : AB = AC. Find the value of theta.



    A teacher gave this question to one of my tutees, probably not realising how hard it is. The best I've done is get to a quartic but I could've made a mistake and I couldn't solve the quartic directly anyway.

    Help!

    (Please post any solutions in spoilers)
    Are we solving it in terms of b or is b to be determined somehow?
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    (Original post by morgan8002)
    Are we solving it in terms of b or is b to be determined somehow?
    Finding it in terms of b would be too easy!

    No you're meant to find the theta angle. The 'b' is not relevant to the question.
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    (Original post by notnek)
    Finding it in terms of b would be too easy!

    No you're meant to find the theta angle. The 'b' is not relevant to the question.
    i'm certain i haven't done this right, i don't think i can actually do this............
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    presumably you mean find theta in terms of b

    :holmes:
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    (Original post by notnek)
    Finding it in terms of b would be too easy!

    No you're meant to find the theta angle. The 'b' is not relevant to the question.
    I got
    Spoiler:
    Show
    90^o
    I have no idea if that's right though. I'm attempting to check but it's a mess.

    edit: No it was wrong. I have another idea though.
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    (Original post by the bear)
    presumably you mean find theta in terms of b

    :holmes:
    You wish.
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    (Original post by notnek)
    The student who was given this question is in Year 13 doing A Level Maths (not further maths).

    I have no idea where the teacher got the question from or if they made it themselves.
    Explains why I could only get this far with my limited gcse knowledge (which is still wrong)



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    (Original post by morgan8002)
    I got
    Spoiler:
    Show
    90^o
    I have no idea if that's right though. I'm attempting to check but it's a mess.
    just checking how that would fit with the other angles around the triangle suggest that you're right,granted i could've made a mistake checking to see if you made one
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    (Original post by drandy76)
    just checking how that would fit with the other angles around the triangle suggest that you're right,granted i could've made a mistake checking to see if you made one
    It would fit. 90 is correct
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    (Original post by drandy76)
    just checking how that would fit with the other angles around the triangle suggest that you're right,granted i could've made a mistake checking to see if you made one
    There's a chance it's correct, but there was a mistake in my working.
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    (Original post by morgan8002)
    I got
    Spoiler:
    Show
    90^o
    I have no idea if that's right though. I'm attempting to check but it's a mess.

    edit: No it was wrong. I have another idea though.
    Wha?

    I just checked using the sine and cosine rules and 90 was fine
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    (Original post by morgan8002)
    I got
    Spoiler:
    Show
    90^o
    I have no idea if that's right though. I'm attempting to check but it's a mess.

    edit: No it was wrong. I have another idea though.
    M8 me and @student403 already vouched pls dont dis this
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    (Original post by Student403)
    Wha?

    I just checked using the sine and cosine rules and 90 was fine
    I'm pretty confused. My last line of working was \cos \frac{\theta}{2} = 0, which I wrote down the wrong solution \theta = 90^o. There was something else that could have been 0 instead which I'm working on now, but I don't see any reason why I would accidentally come up with the right answer.
 
 
 
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