Trig Homework Help!!!!?

Find Sinx

secx= 4/3, tanx is less than 0

sinx=........

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  • TomV
    Lv 7
    8 years ago
    Favorite Answer

    sec(x) = 1/cos(x) = 4/3

    cos(x) = 3/4

    sin(x) = ±√(1-cos²x) = ±√(1-9/16) = ±√7/4

    Since cos(x) > 0, x is in Q1 or Q4. Since tan(x) < 0, x is in Q2 or Q4. Therefore, x must be in Q4 where sin(x) < 0

    sin(x) = -√7/4

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