A particle moves according to the law, `x=acos(pit//2).` . What is the distance covered by it in time interval `t=0` to `t=3` second.

Explanation

To solve the problem, we need to determine the distance covered by the particle moving according to the equation \( x = a \cos\left(\frac{\pi t}{2}\right) \) over the time interval from \( t = 0 \) seconds to \( t = 3 \) seconds.

### Step-by-Step Solution:

1. **Determine the position at \( t = 0 \)**:
\[ x(0) = a \cos\left(\frac{\pi \cdot 0}{2}\right) = a \cos(0) = a \]
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