## L519_x 
'''
Decompress a signal compressed with D6trend.

The vector a below has been obtained as D6trend(f,5).

Decompress a (that is, find A^5(f)) using the systems D2, D4 and D6
(you may need to modify a little the relevant functions used so far). 

Show suitable graphics of the result.
'''

a=[0.366, -1.562, -3.202, 0.937, 4.928, 1.766, -3.252, -2.815, 0.821, 2.151, 0.503, -1.63, -1.667, 1.221, 3.45, 0.513, -4.473, -3.447, 3.093, 5.354, -0.025, -4.575, -2.206, 2.087, 2.186, -0.186, -0.945, -0.229, 0.133, 0.047, 0.001, -0.013]