A. Segitiga Siku-siku

\(\sin \alpha = \dfrac yr = \dfrac {\text{depan}}{\text{miring}}\)
\(\cos \alpha = \dfrac xr = \dfrac {\text{samping}}{\text{miring}}\)
\(\tan \alpha = \dfrac yx = \dfrac {\text{depan}}{\text{samping}}\)
\(\sec \alpha = \dfrac {1}{\cos \alpha} \)
\(\csc \alpha = \dfrac {1}{\sin \alpha} \)
\(\cot \alpha = \dfrac {1}{\tan \alpha} \)
Sudut Istimewa
| \(0\) | \(30^{\text{o}}\) | \(45^{\text{o}}\) | \(60^{\text{o}}\) | \(90^{\text{o}}\) | \(37^{\text{o}}\) | \(53^{\text{o}}\) | |
|---|---|---|---|---|---|---|---|
| Sin | 0 | \(\dfrac{1}{2}\) | \(\dfrac{1}{2}\sqrt{2}\) | \(\dfrac{1}{2}\sqrt{3}\) | 1 | \(0,6\) | \(0,8\) |
| Cos | 1 | \(\dfrac{1}{2}\sqrt{3}\) | \(\dfrac{1}{2}\sqrt{2}\) | \(\dfrac{1}{2}\) | 0 | \(0,8\) | \(0,6\) |
| Tan | 0 | \(\dfrac{1}{3} \sqrt{3}\) | 1 | \(\sqrt{3}\) | ∼ | \(\dfrac 34\) | \(\dfrac 43\) |
B. RELASI SUDUT
1. Kuadran

2. Sudut di kuadran II (\(90^\text{o} < \alpha < 180^\text{o}\))
| Menggunakan \((180^\text{o} - \alpha)\) | Menggunakan \((90^\text{o} + \alpha)\) |
|---|---|
| \begin{equation*}
\begin{split}
& \sin 150^\text{o} = \sin (180^\text{o} - 30^\text{o}) \\\\
& \sin 150^\text{o} = + \sin 30^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\sin 150^\text{o} = + \tfrac 12}
\end{split}
\end{equation*}
150º berada di kuadran II, maka sin 150º bernilai positif. |
\begin{equation*}
\begin{split}
& \sin 150^\text{o} = \sin (90^\text{o} + 60^\text{o}) \\\\
& \sin 150^\text{o} = + \cos 60^\text{o} \quad {\color {blue} \sin \rightarrow \cos}\\\\
& \bbox[5px, border: 2px solid magenta]{\sin 150^\text{o} = + \tfrac 12}
\end{split}
\end{equation*}
150º berada di kuadran II, maka sin 150º bernilai positif. |
| \begin{equation*}
\begin{split}
& \cos 150^\text{o} = \cos (180^\text{o} - 30^\text{o}) \\\\
& \cos 150^\text{o} = - \cos 30^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\cos 150^\text{o} = - \tfrac 12 \sqrt{3}}
\end{split}
\end{equation*}
150º berada di kuadran II, maka cos 150º bernilai negatif. |
\begin{equation*}
\begin{split}
& \cos 150^\text{o} = \cos (90^\text{o} + 60^\text{o}) \\\\
& \cos 150^\text{o} = - \sin 60^\text{o} \quad {\color {blue} \cos \rightarrow \sin}\\\\
& \bbox[5px, border: 2px solid magenta]{\cos 150^\text{o} = - \tfrac 12 \sqrt{3}}
\end{split}
\end{equation*}
150º berada di kuadran II, maka cos 150º bernilai negatif. |
| \begin{equation*}
\begin{split}
& \tan 150^\text{o} = \tan (180^\text{o} - 30^\text{o}) \\\\
& \tan 150^\text{o} = - \tan 30^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\tan 150^\text{o} = - \tfrac 13 \sqrt{3}}
\end{split}
\end{equation*}
150º berada di kuadran II, maka tan 150º bernilai negatif. |
\begin{equation*}
\begin{split}
& \tan 150^\text{o} = \tan (90^\text{o} + 60^\text{o}) \\\\
& \tan 150^\text{o} = - \cot 60^\text{o} \quad {\color {blue} \tan \rightarrow \cot}\\\\
& \bbox[5px, border: 2px solid magenta]{\tan 150^\text{o} = - \tfrac 13 \sqrt{3}}
\end{split}
\end{equation*}
150º berada di kuadran II, maka tan 150º bernilai negatif. |
| \begin{equation*} \begin{split} & \sin 180^\text{o} = \sin (180^\text{o} - 0^\text{o}) \\\\ & \sin 180^\text{o} = \sin 0^\text{o} \\\\ & \bbox[5px, border: 2px solid magenta]{\sin 180^\text{o} = 0} \end{split} \end{equation*} | \begin{equation*} \begin{split} & \sin 180^\text{o} = \sin (90^\text{o} + 90^\text{o}) \\\\ & \sin 180^\text{o} = \cos 90^\text{o} \quad {\color {blue} \sin \rightarrow \cos}\\\\ & \bbox[5px, border: 2px solid magenta]{\sin 180^\text{o} = 0} \end{split} \end{equation*} |
3. Sudut di kuadran III (\(180^\text{o} < \alpha < 270^\text{o}\))
| Menggunakan \((180^\text{o} + \alpha)\) | Menggunakan \((270^\text{o} - \alpha)\) |
|---|---|
| \begin{equation*}
\begin{split}
& \sin 225^\text{o} = \sin (180^\text{o} + 45^\text{o}) \\\\
& \sin 225^\text{o} = − \sin 45^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\sin 225^\text{o} = − \tfrac 12 \sqrt{2}}
\end{split}
\end{equation*}
225º berada di kuadran III, maka sin 225º bernilai negatif. |
\begin{equation*}
\begin{split}
& \sin 225^\text{o} = \sin (270^\text{o} - 45^\text{o}) \\\\
& \sin 225^\text{o} = − \cos 45^\text{o} \quad {\color {blue} \sin \rightarrow \cos}\\\\
& \bbox[5px, border: 2px solid magenta]{\sin 225^\text{o} = − \tfrac 12 \sqrt{2}}
\end{split}
\end{equation*}
225º berada di kuadran III, maka sin 225º bernilai negatif. |
| \begin{equation*}
\begin{split}
& \cos 225^\text{o} = \cos (180^\text{o} + 45^\text{o}) \\\\
& \cos 225^\text{o} = - \cos 45^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\cos 225^\text{o} = - \tfrac 12 \sqrt{2}}
\end{split}
\end{equation*}
225º berada di kuadran III, maka cos 225º bernilai negatif. |
\begin{equation*}
\begin{split}
& \cos 225^\text{o} = \cos (270^\text{o} - 45^\text{o}) \\\\
& \cos 225^\text{o} = - \sin 45^\text{o} \quad {\color {blue} \cos \rightarrow \sin}\\\\
& \bbox[5px, border: 2px solid magenta]{\cos 225^\text{o} = - \tfrac 12 \sqrt{2}}
\end{split}
\end{equation*}
225º berada di kuadran III, maka cos 225º bernilai negatif. |
| \begin{equation*}
\begin{split}
& \tan 225^\text{o} = \tan (180^\text{o} + 45^\text{o}) \\\\
& \tan 225^\text{o} = + \tan 45^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\tan 225^\text{o} = + 1}
\end{split}
\end{equation*}
225º berada di kuadran III, maka tan 225º bernilai positif. |
\begin{equation*}
\begin{split}
& \tan 225^\text{o} = \tan (270^\text{o} - 45^\text{o}) \\\\
& \tan 225^\text{o} = + \cot 45^\text{o} \quad {\color {blue} \tan \rightarrow \cot}\\\\
& \bbox[5px, border: 2px solid magenta]{\tan 225^\text{o} = + 1}
\end{split}
\end{equation*}
225º berada di kuadran III, maka tan 225º bernilai positif. |
| \begin{equation*}
\begin{split}
& \sin 270^\text{o} = \sin (180^\text{o} + 90^\text{o}) \\\\
& \sin 270^\text{o} = -\sin 90^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\sin 270^\text{o} = -1}
\end{split}
\end{equation*}
270º berada di kuadran III atau IV, maka sin 270º bernilai negatif. |
\begin{equation*}
\begin{split}
& \sin 270^\text{o} = \sin (270^\text{o} - 0^\text{o}) \\\\
& \sin 270^\text{o} = -\cos 0^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\sin 270^\text{o} = -1}
\end{split}
\end{equation*}
270º berada di kuadran III atau IV, maka sin 270º bernilai negatif. |
4. Sudut di kuadran IV (\(270^\text{o} < \alpha < 360^\text{o}\))
| Menggunakan \((360^\text{o} - \alpha)\) | Menggunakan \((270^\text{o} + \alpha)\) |
|---|---|
| \begin{equation*}
\begin{split}
& \sin 300^\text{o} = \sin (360^\text{o} - 60^\text{o}) \\\\
& \sin 300^\text{o} = - \sin 60^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\sin 300^\text{o} = - \tfrac 12 \sqrt{3}}
\end{split}
\end{equation*}
300º berada di kuadran IV, maka sin 300º bernilai negatif. |
\begin{equation*}
\begin{split}
& \sin 300^\text{o} = \sin (270^\text{o} + 30^\text{o}) \\\\
& \sin 300^\text{o} = - \cos 30^\text{o} \quad {\color {blue} \sin \rightarrow \cos}\\\\
& \bbox[5px, border: 2px solid magenta]{\sin 300^\text{o} = - \tfrac 12 \sqrt{3}}
\end{split}
\end{equation*}
300º berada di kuadran II, maka sin 300º bernilai positif. |
| \begin{equation*}
\begin{split}
& \cos 300^\text{o} = \cos (360^\text{o} - 60^\text{o}) \\\\
& \cos 300^\text{o} = + \cos 60^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\cos 300^\text{o} = + \tfrac 12}
\end{split}
\end{equation*}
300º berada di kuadran IV, maka cos 300º bernilai positif. |
\begin{equation*}
\begin{split}
& \cos 300^\text{o} = \cos (270^\text{o} + 30^\text{o}) \\\\
& \cos 300^\text{o} = + \sin 30^\text{o} \quad {\color {blue} \cos \rightarrow \sin}\\\\
& \bbox[5px, border: 2px solid magenta]{\cos 300^\text{o} = + \tfrac 12}
\end{split}
\end{equation*}
300º berada di kuadran II, maka cos 300º bernilai negatif. |
| \begin{equation*}
\begin{split}
& \tan 300^\text{o} = \tan (360^\text{o} - 60^\text{o}) \\\\
& \tan 300^\text{o} = - \tan 60^\text{o} \\\\
& \bbox[5px, border: 2px solid magenta]{\tan 300^\text{o} = - \sqrt{3}}
\end{split}
\end{equation*}
300º berada di kuadran IV, maka tan 300º bernilai negatif. |
\begin{equation*}
\begin{split}
& \tan 300^\text{o} = \tan (270^\text{o} + 30^\text{o}) \\\\
& \tan 300^\text{o} = - \cot 30^\text{o} \quad {\color {blue} \tan \rightarrow \cot}\\\\
& \bbox[5px, border: 2px solid magenta]{\tan 300^\text{o} = - \sqrt{3}}
\end{split}
\end{equation*}
300º berada di kuadran II, maka tan 300º bernilai negatif. |
C. KOORDINAT KUTUB
Koordinat Cartesian

Menentukan koordinat Cartesian
\(x = r \:.\: \cos \theta\)
\(y = r \:.\: \sin \theta\)
Koordinat Kutub

Menentukan koordinat kutub
\(r = \sqrt{x^2 + y^2}\)
\(\tan \theta = \dfrac yx\) → cek kuadran