Let the function be .

Draw a coordinate plane.

Graph the function .

Graph : \ \

Observe the graph of the function :

The graph of is the same as .

Thus, the expression is equals to the trigonometric function .

Algebraic conformation : \ \

The expression is .

Consider .

Apply reciprocal identities :

                                                  .

Apply quotient identity : .

Apply LCM rule : .

Apply Pythagorean identity : .

Apply quotient identity : .

.

Thus, .

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