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Use identities to find tan, csc, sec, and cot. Where necessary, rationalize denominators

Use identities to find tan, csc, sec, and cot. Where necessary, rationalize denominators-example-1
User Amol Fasale
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1 Answer

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20 votes

We are given:


sin\text{ }\theta=(3)/(5),cos\text{ }\theta=(4)/(5)

The tangent is defined as the ratio of the sine and the cosine:


tan\text{ }\theta=\frac{sin\text{ }\theta}{cos\text{ }\theta}

Calculating:


\begin{gathered} tan\text{ }\theta=((3)/(5))/((4)/(5))=(3)/(5)\cdot(5)/(4) \\ \\ tan\text{ \theta}=(3)/(4) \end{gathered}

The cotangent is the reciprocal of the tangent:


\begin{gathered} \cot\theta=(1)/(\tan\theta) \\ \\ \cot\theta=(1)/((3)/(4))=(4)/(3) \end{gathered}

The secant is the reciprocal of the cosine:


\begin{gathered} \sec\theta=(1)/(\cos\theta)=(1)/((4)/(5)) \\ \\ \sec\theta=(5)/(4) \end{gathered}

The cosecant is the reciprocal of the sine:


\begin{gathered} \csc\theta=(1)/(\sin\theta)=(1)/((3)/(5)) \\ \\ \csc\theta=(5)/(3) \end{gathered}

User Kamini
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