The disturbance of a wave is represented by the equation `y(x, t) = 0.04 cos (100 pi t + (pi)/(2)) cos (20 pi x)` x, y are in m and t is in second.
Find the positions at which
(a) a node will be formed.
(b) an antinode will be formed.
Also find speed and wavelength of the wave.

Explanation

To solve the problem, we will analyze the given wave disturbance equation step by step.

### Given:
The wave disturbance is represented by the equation:
\[ y(x, t) = 0.04 \cos(100 \pi t + \frac{\pi}{2}) \cos(20 \pi x) \]

### Step 1: Identify the parameters
From the equation, we can identify:
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