The equation is .

Let the functions are and .

Draw a coordinate plane.

Graph the function .

Graph the function .

Observe the above two graphs :

The graphs appears to be the same.

So, the equation appears to be an identity.

Check algebraically :

The identity is .

Consider left hand side identity : .

Reciprocal identities : .

Quotient identity : .

Pythagorean identity : .

= Right hand side identity.

The equation represents an identity.