>>261
a = 3 => |a| = |3| = 3, |a-2√2| = 3 - 2√2 (≒ 0.172) , |a-4| = |3 - 4| = |-1| = 1
∴P = 3 - (3-2√2) - 1 = -1 + 2√2

a = -1 => |a| = |-1| = 1, |a-2√2| = |-1-2√2| = 1+2√2 , |a-4| = |-1 - 4| = |-5| = 5
∴P = 1 - (1+2√2) - 5 = -5 - 2√2

0<a<2√2 => |a| = a (∵a>0) , |a-2√2| = 2√2 - a (∵a < 2√2) , |a-4| = 4 - a (∵a < 2√2 < 4)
あとガンガレ