bonjour
je te propose
( 3 - √5) / ( 1 - √2)
= ( 3 - √5 * √2 ) / ( 1 - √2*√2 )
= 3 - √10 / 1 - 2
= 3 - √10) / - 1
= - 3 - √10
[( 1 + √5 ) / ( 1 - √5 ) ]²
= ( 1 + 2 √5 + 5 ) / ( 1 - 2 √5 + 5 )
= 6/6 = 1
- 1 ≤ x ≤ 2
x ∉ [ - 1 : 2 ]
- 4 < x ≤ 2
x ∈ ] - 4 : 2 ]
5 < x < 2
ensemble disjoint
