Question

Di ketahui log 2=0,3010; log 3=0,4771 dan log 7=0,8451 tentukan:

a.log 18

b.log 21

c.log 10,5

d.log1/7^-1

Answer 1

A) Log 18
= log (2*3*3)
=log 2 + log 3 +log 3
= 0,3010 + 0,4771 + 0,4771
=1,2552

B) log 21
= log (3*7)
= log 3 + log 7
= 0,4771 + 0,8451
= 1,3222

C) log 10,5
= log (3*7:2)
= log 3 + log 7 - log 2
= 0,4771 + 0,8451 - 0,3010
= 1,6231

D) log 1/7
= log 7⁻¹
= -1 log 7 = -1 . 0,8451
= -0,8451