You can put this solution on YOUR website! suppose tan A =(3/4) and 180
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tan = y/x
In QIII, y and x are both negative.
y = -3 ; x = -4
r = sqrt[3^2+4^2] = 5
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Note:: cos(A) = x/r = -4/5
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sin(1/2 A) = sqrt[(1-(-4/5))/2]
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cos(1/2 A) = sqrt[1+(-4/5))/2]
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tan(1/2 A) = (1-cos(x))/sin(x) = (1-(-4/5))/(-3/5)
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Cheers,
Stan H.
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