Show That the Equation Is Not an Identity by Finding $$\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?$$

question 39

Multiple Choice

Show that the equation is not an identity by finding a value of x for which both sides are defined but not equal.
- $$\frac { \sin 3 x + \sin 9 x } { \cos 9 x - \cos 3 x } = ?$$

• A) \(- \cot 3 x\)
• B) \(\tan 3 x + \tan 9 x\)
• C) \(\cot 3 x\)
• D) \(\tan 6 x\)

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Definitions:

F-statistic

A ratio of variances that is used to test the overall significance of a multiple regression model; it compares model fit versus random variance.

Coefficient of Determination

A statistical measure used to analyze how differences in one variable can be predicted by a difference in a second variable.

Coefficient of Determination

A statistical measure that determines the proportion of the variance in the dependent variable that can be predicted from the independent variable(s).

Multiple Regression

An approach in statistics that leverages various independent variables to estimate the outcome of a target variable.