Question

Diketahui log 2 = 0,3010 ;log 3: 1,4771 dan log 7 =0,8451 tentukan
a. log 18
b. log 21
c.. log 10,5
d. log 1/7

Answer 1


a. log 18
b. log 21
c.. log 10,5
d. log 1/7
jb :
log 2 = 0,3010, lg 3 = 0,4771 dan log 7 = 0,8451

a) log 18 = log(3² * 2)
= log 3² + log 2
= 2 * log 3 + log 2 = 2(0,4771) + (0,3010)
= 1.2552

b. log 21 = log(7 * 3)
= log 7 + log 3 = 0,8451 + 0,4771
= 1.3222

c. log 10,5 = log(105/10)
= log(3 * 5 * 7) / 10)
= log 3 + log 5 + log 7 - log 10
= 0,3010 + 0,4771 + 0,8451 - 1
= 0.6232

d. log (1/7) = log 7^-1 = -log 7
= -0,8451