Sum and Difference Identities: Sine/Cosine

Rewrite  $\sin\left(x+y\right)$  

•  $\sin x\cos y-\cos x\sin y$  

•  $\sin x\cos y+\cos x\sin y$  

•  $\cos x\cos y+\sin x\sin y$  

•  $\cos x\cos y-\sin x\sin y$  

Rewrite  $\cos\left(x+y\right)$  

•  $\sin x\cos y+\cos x\sin y$  

•  $\sin x\cos y-\cos x\sin y$  

•  $\cos x\cos y-\sin x\sin y$  

•  $\cos x\cos y+\sin x\sin y$  

Rewrite  $\sin\left(x-y\right)$  

•  $\sin x\cos y-\cos x\sin y$  

•  $\sin x\cos y+\cos x\sin y$  

•  $\cos x\cos y+\sin x\sin y$  

•  $\cos x\cos y-\sin x\sin y$  

Rewrite  $\cos\left(x-y\right)$  

•  $\sin x\cos y+\cos x\sin y$  

•  $\sin x\cos y-\cos x\sin y$  

•  $\cos x\cos y-\sin x\sin y$  

•  $\cos x\cos y+\sin x\sin y$  

Which is equivalent to   $\sin30\cos60+\cos30\sin60$  

•  $\sin90$  

•  $\sin30$  

•  $\cos90$  

•  $\cos30$  

Which is equivalent to   $\sin100\cos20-\cos100\sin20$  

•  $\sin120$  

•  $\sin80$  

•  $\cos120$  

•  $\cos80$  

Which is equivalent to   $\cos45\cos30-\sin45\sin30$  

•  $\sin75$  

•  $\sin15$  

•  $\cos75$  

•  $\cos15$  

Which is equivalent to   $\cos95\cos10+\sin95\sin10$  

•  $\sin105$  

•  $\sin85$  

•  $\cos105$  

•  $\cos85$