対称性
\(\sin\left(-\theta\right)=-\sin\theta\)
\(\cos\left(-\theta\right)=\cos\theta\)
\(\tan\left(-\theta\right)=-\tan\theta\)

対称性
\(\sin\left(\theta+\pi\right)=-\sin\theta\)
\(\cos\left(\theta+\pi\right)=-\cos\theta\)
\(\tan\left(\theta+\pi\right)=\tan\theta\)

対称性　(垂直条件)
\(\sin\left(\theta+\dfrac{\pi}{2}\right)=\cos\theta\)
\(\cos\left(\theta+\dfrac{\pi}{2}\right)=-\sin\theta\)
\(\tan\left(\theta+\dfrac{\pi}{2}\right)=-\dfrac{1}{\tan\theta}\)

対称性　(垂直条件)
\(\sin\left(\theta-\dfrac{\pi}{2}\right)=-\cos\theta\)
\(\cos\left(\theta-\dfrac{\pi}{2}\right)=\sin\theta\)
\(\tan\left(\theta-\dfrac{\pi}{2}\right)=-\dfrac{1}{\tan\theta}\)

\(\sin\left(\theta+\dfrac{\pi}{6}\right)\)
\(\cos\left(\theta-\dfrac{\pi}{3}\right)\)
\(\tan\left(\theta+\dfrac{\pi}{4}\right)\)
など，どうなるのだろうか？