A thief stole a sine and a cosine.

He took the two identities to a beach. However, they were too heavy for him to carry. He wanted to keep them under the sand, but the beach was so narrow that it could only contain one of them: sine or cosine.

He decided that, using his mathematical skills, that he would stack sine over cosine – but that resulted in tan! He did not want to get tan. So he stacked cosine over sine…

and then he got cot.