C2 trigonometry

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  1. najinaji's Avatar
    • Vengeful, Imperial Overlord of The Student Room
    • Location: London
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    C2 trigonometry
    The question is:

    'Find the two possible triangles ABC which satisfy b=5, a=3, A=35' '

    I found the first triangle, where B=72.9', C=72.1' and c=4.98. How do I find the other one?
  2. steve10's Avatar
    • Exalted and Worshipped Member
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    Re: C2 trigonometry
    The angle B can have two values, because sin(B) = sin(180-B)
    Let Beta = 180 - B.
    Your second triangle has an angle Beta, say, rather than B, and still have the same characteristics as the triangle with an angle = B.
  3. najinaji's Avatar
    • Vengeful, Imperial Overlord of The Student Room
    • Location: London
    • Posts: 3,677
    Re: C2 trigonometry
    (Original post by steve10)
    The angle B can have two values, because sin(B) = sin(180-B)
    Let Beta = 180 - B.
    Your second triangle has an angle Beta, say, rather than B, and still have the same characteristics as the triangle with an angle = B.
    Ohhh, I see. Thank you.
  4. George_'s Avatar
    • Exalted Member
    • Posts: 320
    Re: C2 trigonometry
    Couldn't you use the cosine rule? Or is there not enough data ? :P

    Or even the sine rule?
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