Evaluate the following:
i) `cos120^(@)sin390^(@)+cos330^(@)cos150^(@)`
ii) `sin^(2)(3pi)/(4)+cos^(2)pi/4+sec^(2)pi/3`

Explanation

Let's evaluate the given expressions step by step.

### Part i: Evaluate `cos(120°)sin(390°) + cos(330°)cos(150°)`

1. **Evaluate `cos(120°)`**:
- We can express \( 120° \) as \( 180° - 60° \).
- Hence, \( \cos(120°) = -\cos(60°) = -\frac{1}{2} \).

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