# Product identities

The product relation of a trigonometric function with another trigonometric function is called product identity.

## Introduction

Every trigonometric function has a special relation with another trigonometric function in product form. So, the six trigonometric ratios form three product trigonometric identities and they are used as formulas in trigonometry.

### Sine and Cosecant functions

The product of sin and cosecant functions at an angle of a right triangle is equal to one.

$\sin{\theta}\csc{\theta} \,=\, 1$

### Cosine and Secant functions

The product of cos and secant functions at an angle of a right triangle is equal to one.

$\cos{\theta}\sec{\theta} \,=\, 1$

### Tangent and Cotangent functions

The product of tan and cot functions at an angle of a right triangle is equal to one.

$\tan{\theta}\cot{\theta} \,=\, 1$

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