For three vectors , `vecX, vecY and vecZ, vecZ=vecX+vecY and |vecX|=12, |vecY|=5 and |vecZ|=13`
Calculate the angle between `vecY and vecZ`.

Explanation

To find the angle between the vectors \(\vec{Y}\) and \(\vec{Z}\), we can use the cosine rule in vector form. Given that \(\vec{Z} = \vec{X} + \vec{Y}\), we can express the magnitudes of the vectors and apply the cosine rule.

### Step-by-step Solution:

1. **Write down the given information:**
- \(|\vec{X}| = 12\)
- \(|\vec{Y}| = 5\)
- \(|\vec{Z}| = 13\)
...