Question 736023: if cosŲ = -3/5 and sinŲ < 0
find tanŲ (nearest fourth decimal digit)
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! if cosŲ = -3/5 and sinŲ < 0
find tanŲ (nearest fourth decimal digit)
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If cos and sin are both negative theta is in QIII.
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Since cos = x/r = -3/5, x = -3 and r = 5
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Solve for "y":
y = sqrt[r^2 - x^2] = sqrt[25-9] = sqrt(16) = 4
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But y is negative in QIII, so y = -4
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Tan is positive in QIII:
tan(theta) = y/x = -4/-3 = 4/3
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Cheers,
Stan H.
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