【忘れても大丈夫！】サインコサインの変換公式、覚え方とコツ→単位円を描こう！ - 青春マスマティック

$$\cos\left(90^{\circ}+\theta\right) = - \sin \theta$$ $$\sin\left(90^{\circ}+\theta\right) = \cos \theta$$ $$\cos\left(180^{\circ}+\theta\right) = - \cos \theta$$ $$\sin\left(180^{\circ}+\theta\right) = - \sin \theta$$ $$\cos\left(-\theta\right) = \cos \theta$$ $$\sin\left(-\theta\right) = - \sin \theta$$ $$\cos\left(90^{\circ}-\theta\right) = \sin \theta$$ $$\sin\left(90^{\circ}-\theta\right) =