SOLUTION: Given that pie lesser than theta lesser than 2/3pie and sin theta = -1/4 using trigonometric formulas to find the exact value of the following.
cos(2theta)
cos theta
sin(2theta)
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-> SOLUTION: Given that pie lesser than theta lesser than 2/3pie and sin theta = -1/4 using trigonometric formulas to find the exact value of the following.
cos(2theta)
cos theta
sin(2theta)
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Question 844538: Given that pie lesser than theta lesser than 2/3pie and sin theta = -1/4 using trigonometric formulas to find the exact value of the following.
cos(2theta)
cos theta
sin(2theta) Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! Given that pie<= t <=(3/2)pi and sin theta = -1/4 using trigonometric formulas to find the exact value of the following.
Note: t is in QIII where both x and y are negative
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Since sin(t) = -1/4, cos(t) = -sqrt(4^2-1^2)/4 = -sqrt(15)/4
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cos(2t) = 1 - 2sin^2(t) = 1-2(-1/4)^2 = 7/8
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cos(t) = -sqrt(15)/4
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sin(2theta) = 2sin(t)cos(t) = 2(-1/4)(-sqrt(15)/4 = sqrt(15)/8
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Cheers,
Stan H.
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