This prompt performs MDCT step-by-step for multimedia compression assignment.
来源：https://prompts.chat/prompts/cmo4g22dq0001l504srir0qef
Implement MDCT for the input sequence:
x(n) = [1, 2, 3, 4]
Steps:
1. Identify N and 2N
2. Apply MDCT formula
3. Show cosine values clearly
4. Display step-by-step calculation table
5. Give final coefficients
