Regles d'exponent, lleis d'exponent i exemples.
La base a elevada a la potència de n és igual a la multiplicació de a, n vegades:
a n = a × a × ... × a
n vegades
a és la base i n és l'exponent.
31 = 3
32 = 3 × 3 = 9
33 = 3 × 3 × 3 = 27
34 = 3 × 3 × 3 × 3 = 81
35 = 3 × 3 × 3 × 3 × 3 = 243
Nom de la regla | Regla | Exemple |
---|---|---|
Normes de producte | a n ⋅ a m = a n+m | 2 3 ⋅ 2 4 = 2 3+4 = 128 |
a n ⋅ b n = ( a ⋅ b ) n | 3 2 ⋅ 4 2 = (3⋅4) 2 = 144 | |
Regles de quocient | a n / a m = a n - m | 2 5 / 2 3 = 2 5-3 = 4 |
a n / b n = ( a / b ) n | 4 3 / 2 3 = (4/2) 3 = 8 | |
Regles de poder | ( b n ) m = b n⋅m | (2 3 ) 2 = 2 3⋅2 = 64 |
b n m = b ( n m ) | 2 3 2 = 2 ( 3 2 ) = 512 | |
m √( b n ) = b n / m | 2 √(2 6 ) = 2 6/2 = 8 | |
b 1/ n = n √ b | 8 1/3 = 3 √ 8 = 2 | |
Exponents negatius | b -n = 1 / b n | 2 -3 = 1/2 3 = 0,125 |
Zero regles | b 0 = 1 | 5 0 = 1 |
0 n = 0, per a n >0 | 05 = 0 | |
Una regla | b 1 = b | 5 1 = 5 |
1 n = 1 | 15 = 1 | |
Menys una regla | (-1) 5 = -1 | |
Regla derivada | ( x n ) ' = n ⋅ x n -1 | ( x 3 ) ' = 3⋅ x 3-1 |
Regla integral | ∫ x n dx = x n +1 /( n +1)+ C | ∫ x 2 dx = x 2+1 /(2+1)+ C |
an ⋅ am = an+m
Exemple:
23 ⋅ 24 = 23+4 = 27 = 2⋅2⋅2⋅2⋅2⋅2⋅2 = 128
an ⋅ bn = (a ⋅ b)n
Exemple:
32 ⋅ 42 = (3⋅4)2 = 122 = 12⋅12 = 144
Vegeu: Multiplicació d'exponents
an / am = an-m
Exemple:
25 / 23 = 25-3 = 22 = 2⋅2 = 4
an / bn = (a / b)n
Exemple:
43 / 23 = (4/2)3 = 23 = 2⋅2⋅2 = 8
Vegeu: Divisió d'exponents
(an) m = a n⋅m
Exemple:
(23)2 = 23⋅2 = 26 = 2⋅2⋅2⋅2⋅2⋅2 = 64
a nm = a (nm)
Exemple:
232 = 2(32) = 2(3⋅3) = 29 = 2⋅2⋅2⋅2⋅2⋅2⋅2⋅2⋅2 = 512
m√(a n) = a n/m
Exemple:
2√(26) = 26/2 = 23 = 2⋅2⋅2 = 8
b-n = 1 / bn
Exemple:
2-3 = 1/23 = 1/(2⋅2⋅2) = 1/8 = 0.125
Vegeu: Exponents negatius
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