Express `cos130^(@)` in terms of `theta_(R)`.

Explanation

To express \( \cos 130^\circ \) in terms of the reference angle \( \theta_R \), we can follow these steps:

### Step 1: Identify the Quadrant
The angle \( 130^\circ \) lies in the second quadrant, where cosine values are negative.

### Step 2: Calculate the Reference Angle
The reference angle \( \theta_R \) is calculated by subtracting the given angle from \( 180^\circ \):
\[
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