Interchange the variables.

Rewrite the equation as .

Divide each term by and simplify.

Divide each term in by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Move the negative in front of the fraction.

Take the inverse cosine of both sides of the equation to extract from inside the cosine.

Divide each term by and simplify.

Divide each term in by .

Cancel the common factor of .

Cancel the common factor.

Divide by .

Replace the with to show the final answer.

Set up the composite result function.

Evaluate by substituting in the value of into .

Cancel the common factor of and .

Factor out of .

Cancel the common factors.

Factor out of .

Cancel the common factor.

Rewrite the expression.

Divide by .

Since , is the inverse of .

Find the Inverse -7cos(6x)