Write the solution set of the equation `(2costheta+1)(4costheta+5)=0` in the interval `[0,2pi]`

Explanation

To solve the equation \((2 \cos \theta + 1)(4 \cos \theta + 5) = 0\) in the interval \([0, 2\pi]\), we will follow these steps:

### Step 1: Set each factor to zero
Since the product of two numbers is zero, at least one of the factors must be zero. Therefore, we can set up two separate equations:
1. \(2 \cos \theta + 1 = 0\)
2. \(4 \cos \theta + 5 = 0\)

### Step 2: Solve the first equation
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