Chapitre 4 Racine carrée

a
a a
a√a
√a≥0 (√a)2=a
√
√5 (√5)2= 5
√36 62= 36 6 ≥0
√36 = 6
12= 1 1 ≥0√1=1
02= 0 0 ≥0√0=0
√25 = √52= 5 √81 = √92= 9 √144 = √122= 12

√8 22= 4 32= 9
2<√8<3√8≈2,83
√120 112= 121
√120 √120 ≈10,95
a b
√ab =√a×√b
√30 = √3×10 = √3×√10
√20 = √4×5 = √4×√5=2√5 4×5
2×10
√125 = √25 ×5 = √25 ×√5 = 5√5
a b b
ra
b=√a
√b
r32
25 =√32
√25 =√16 ×2
5=4√2 5
r75
8=√75
√8=√25 ×3 √4×2=5√3
2√2

Q
5∈Q5 = 5
1N
−8∈Q−8 = −8
1Z
12,14 ∈Q12,14 = 1214
100 D
N⊂Z⊂D⊂Q
√2π