In this tutorial we shall study certain combination of and , called hyperbolic functions. These functions have numerous applications and arise naturally in many mathematical problems. It will become evident as we progress that the hyperbolic functions have many properties in common with the trigonometric functions.

**Hyperbolic Sine Function:**

The hyperbolic sine function, denoted by , and is defined as

**Hyperbolic Cosine Function:**

The hyperbolic cosine function, denoted by , and is defined as

**Hyperbolic Tangent Function:**

The hyperbolic tangent function, denoted by , and is defined as

**Hyperbolic Cotangent Function:**

The hyperbolic cotangent function, denoted by , and is defined as

**Hyperbolic Secant Function:**

The hyperbolic secant function, denoted by , and is defined as

**Hyperbolic Cosecant Function:**

The hyperbolic cosecant function, denoted by , and is defined as