log help!!!!

[NOORALLAH]

So I can't get this right without a calculator!!!!! can some one explain how can to do log without a calculator....
how is the log (1.3*10^-3) lower than 3 and approximately 2.9!!!!

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[needzmoar]

So I can't get this right without a calculator!!!!! can some one explain how can to do log without a calculator....
how is the log (1.3*10^-3) lower than 3 and approximately 2.9!!!!

you're missing a negative sign


Logarithmic properties

log[a*b] = log[a]+log

log[a^b] = b*log[a]


-log[1.3*10^-3] = -log[1.3] + -(-3)log[10] = -.1 + 3 = 2.9

We know that log[1]=0 so log[1.3] should be slightly greater zero (.1)

 

[NOORALLAH]

waw you made it so easy!!!! Thanks a lot!!!

 

[needzmoar]

waw you made it so easy!!!! Thanks a lot!!!