Réponses

2014-05-06T16:12:34+02:00
Exercice 106
1) a. A = 1.2 x 10^5 x 7 x 10^-8 (^ se lit puissance)
A = 8.4 x 10^(5-8) = 8.4 x 10^-3
A = 0.0084

b) B = (24 x 10^5)/(32 x 10-3)
B = 24 x 10^5 x 10^3 /32 = 10^(5+3) x 3/4
B = 0,75 x10^8
B = 7,5 x 10^7

C = (25 x 10^3 x 21 x 10^7) / (35 x 10^2)
C = 10^3 x 10^7 x 10^-2 x 25 x 21 / 35
C = 10^(3+7-2) x 5x5 x 3x7 / 5x7
C = 10^8 x5 x 3
C = 15 x 10^8
C = 1,5 x10^9

2) A x B = 8,4 x 10^-3 x 7,5 x 10^7
A x B = 8,4 x 7,5 x 10^4
A x B = 64 x 10^4
A x B = 6,4 x 10^5

B/C = (7,5 x 10^7) / (1,5 x10^9)
B/C = 10^7 x 10^-9 x 7.5/1.5
B/C = 5 x 10^-2

B + C = (7,5 x 10^7) + (1,5 x 10^9)
B + C = (0,075 x 10^9) + (1,5 x 10^9)
B + C = (0,075 + 1,5) x 10^9
B + C = 1,575 x 10^9