Evaluate the following: `sin 78^@ cos 18^@-cos 78^@ sin 18^@`

Explanation

To evaluate the expression \( \sin 78^\circ \cos 18^\circ - \cos 78^\circ \sin 18^\circ \), we can use the sine subtraction formula.

### Step-by-Step Solution:

1. **Identify the Formula**: We recognize that the expression resembles the sine subtraction formula:
\[ \sin(a - b) = \sin a \cos b - \cos a \sin b \]
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