Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 month ago

help with this trig question!?

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3 Answers

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  • Anonymous
    1 month ago
    Favorite Answer

    x = 2/3.......

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  • Vaman
    Lv 7
    1 month ago

    cos x=5/13, sin x= sqrt(13^2-5^2)/13=12/13. Tan x= 12/5

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  • Anonymous
    1 month ago

    The easiest way to solve this is with the tangent half angle formula (they are really 3 formulas below):

    tan(Ѳ/2) = ±√((1 - cos(Ѳ))/(1 + cos(Ѳ))) = sin(Ѳ)/(1-cos(Ѳ)) = csc(Ѳ) - cot(Ѳ)

    https://en.wikipedia.org/wiki/List_of_trigonometri...

    The first one, ±√((1 - cos(Ѳ))/(1 + cos(Ѳ))), is what you need, since you know

     cos(Ѳ) = 5/3. 

    So just plug it in:

    tan(Ѳ/2) = ±√((1 - (5/3))/(1 + (5/3)))

    There are 2 potential solutions, a positive and negative one.

    There are a lot of trig identities, and it's hard to remember them all. If you can, I recommend looking them up from a table. If you have to memorize them, then memorize the most basic ones first, and try to be able to derive the more complicated ones without needing to memorize them.

    Source(s): Blessed enough to go to school
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