Prove $\frac { \sin ( x + y ) } { \sin x \sin y } = \cot x + \cot y$

question 99

Essay

Prove $\frac { \sin ( x + y ) } { \sin x \sin y } = \cot x + \cot y$ .

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Definitions:

Teeth

Hard, calcified structures in the jaws of many vertebrates, used for biting, chewing, and sometimes for defense.

Grow Continuously

A process referring to entities that do not stop increasing in size or number over time, either naturally or through external intervention.

Birds

Warm-blooded vertebrates characterized by feathers, beaks, and typically the ability to fly, with some exceptions like ostriches.

Gizzard

Of birds and some other animals, a digestive chamber lined with a hard material that grinds up food.