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Given cosθ=3/5 and 270°<θ<360° , find the exact value of each expression.

cotθ/2

User UVic
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1 Answer

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270^(\circ) < \theta < 360^(\circ) \implies 135^(\circ) < (\theta)/(2) < 180^(\circ) \implies \cot (\theta)/(2) < 0


\tan (\theta)/(2)=-\sqrt{(1-\cos \theta)/(1+\cos \theta)}=-\sqrt{(1-(3)/(5))/(1+(3)/(5))}=-(1)/(2)


\cot (\theta)/(2)=(1)/(\tan (\theta)/(2))=\boxed{-2}

User Amphibient
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