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Trig help me find the other five trig values deep explanatory needed pls #5

Trig help me find the other five trig values deep explanatory needed pls #5-example-1
User Artem Shafranov
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1 Answer

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As we can see, the sine and the cosine are negative:


\begin{gathered} \cos\theta=-(√(10))/(5) \\ \\ \sin\theta\lt0 \end{gathered}

This is true for angles in the third quadrant:


180\degree\lt\theta\lt270\degree

Then, using the cosine value, we can find the remaining side. From the Pythagorean Theorem:


\begin{gathered} CO^2+CA^2=H^2 \\ \\ CO^2+10=25 \\ \\ \Rightarrow CO=-√(15) \end{gathered}

Then, the remaining trigonometric functions are:


\sin\theta=-(√(15))/(5)
\begin{gathered} \tan\theta=(-√(15))/(-√(10))=(√(15)\cdot√(10))/(10) \\ \\ \Rightarrow\tan\theta=(√(6))/(2) \end{gathered}
\begin{gathered} \sec\theta=(1)/(\cos\theta)=-(5)/(√(10))\cdot(√(10))/(√(10)) \\ \\ \Rightarrow\sec\theta=-(√(10))/(2) \end{gathered}
\begin{gathered} \csc\theta=(1)/(\sin\theta)=-(5)/(√(15))\cdot(√(15))/(√(15)) \\ \\ \Rightarrow\csc\theta=-(√(15))/(3) \end{gathered}
\begin{gathered} \ctg\theta=(1)/(\tan\theta)=(2)/(√(6))\cdot(√(6))/(√(6)) \\ \\ \Rightarrow\ctg\theta=(√(6))/(3) \end{gathered}

User Red Lv
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