Question 1005715
 Suppose cosθ= 2/5 and θ is in quadrant IV. 
Use the Fundamental Trigonometric Identities to find sin θ. 
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Note: x is positive and y is negative in QIV.
By definition cos(t) = x/r
So, x = 2 and r = 5
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Then y = -sqrt[5^2-2^2] = -sqrt(21)
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Ans: sin(t) = y/r = -sqrt(21)/5
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Cheers,
Stan H.
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