Regles d'exponent, lleis de l'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.
3 1 = 3
3 2 = 3 × 3 = 9
3 3 = 3 × 3 × 3 = 27
3 4 = 3 × 3 × 3 × 3 = 81
3 5 = 3 × 3 × 3 × 3 × 3 = 243
Nom de la regla | Regla | Exemple |
---|---|---|
Normes del 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 del quocient | a n / a m = a n - m | 2 5 /2 3 = 2 5-3 = 4 |
a n / b n = ( a / b ) n | 4 març / 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 |
Regles zero | b 0 = 1 | 5 0 = 1 |
0 n = 0, per a n / 0 | 0 5 = 0 | |
Una regla | b 1 = b | 5 1 = 5 |
1 n = 1 | 1 5 = 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 |
a n ⋅ a m = a n + m
Exemple:
2 3 ⋅ 2 4 = 2 3 + 4 = 2 7 = 2⋅2⋅2⋅2⋅2⋅2⋅2 = 128
a n ⋅ b n = ( a ⋅ b ) n
Exemple:
3 2 ⋅ 4 2 = (3⋅4) 2 = 12 2 = 12⋅12 = 144
Vegeu: Multiplicar exponents
a n / a m = a n - m
Exemple:
2 5 /2 3 = 2 5-3 = 2 2 = 2⋅2 = 4
a n / b n = ( a / b ) n
Exemple:
4 març / 2 3 = (4/2) 3 = 2 3 = 2⋅2⋅2 = 8
Vegeu: Dividir els exponents
( a n ) m = a n⋅m
Exemple:
(2 3 ) 2 = 2 3⋅2 = 2 6 = 2⋅2⋅2⋅2⋅2⋅2 = 64
a n m = a ( n m )
Exemple:
2 3 2 = 2 (3 2 ) = 2 (3⋅3) = 2 9 = 2⋅2⋅2⋅2⋅2⋅2⋅2⋅2⋅2 = 512
m √ ( a n ) = a n / m
Exemple:
2 √ (2 6 ) = 2 6/2 = 2 3 = 2⋅2⋅2 = 8
b -n = 1 / b n
Exemple:
2 -3 = 1/2 3 = 1 / (2⋅2⋅2) = 1/8 = 0,125
Vegeu: Exponents negatius