Question

log2=0.3010 log3=0.4771 simplify log20

I'm stuck at log2+log2+log5, if i split up the log5, i would get log(2+3) but that isn't the same as log2+log3 so i'm probably missing something or using the wrong factors to start with... what am i supposed to do?

Answer 1

i think you are right, there is no way of getting log(20) in terms of log(3)

Answer 2

thanks for the confirmation, i thought i was lost

Answer 3

But i think you can with
\[\log(4*5) = \log4 + \log5\]

Answer 4

it's the same thing i expanded, but apparently you're supposed to use the values they gave you...

Answer 5

ohh, but 2 and 3 won't work; so i thought of another approach..

Answer 6

probably, u can use log 60 = log 2 + log 3 + log 10. It has the same meaning with
log 60 = 2*log 2 + log 3 + log 5. so u can getting log 5 there.
Compare
log 60 = log 2 + log 3 + log 10.......(1)
log 60 = 2*log 2 + log 3 + log 5.....(2)
so
log 2 + log 3 + log 10 = 2*log 2 + log 3 + log 5
log 5 = log 2 + log 3 + log 10 - 2*log 2 - log 3
then u can getting log 5 from here.
log 20 = 2*log 2 + log 5
then substitute log 5, that we have had found.

Perhaps, the way that i had given to u, can helping u to solve this problem.

Thank you

Answer 7

log20 = log(2x10) = log2+log10 = log2+1 = 0.3010 +1 = 1.3010
then you can finish the task with the given value the a truth :)

Answer 8

it doesn't state that you must use the value log3 !

Answer 9

wow, amazing. how fool i am. i was thinking too far. hehe

Answer 10

20 = 2 * 10
-> log( 2 * 10) = log2 + log10 = .3010 + 1 = 1.3010