2007-12-10 17:07:08 · 2 answers · asked by Francisco C 2 in Science & Mathematics ➔ Mathematics
Let log = log to base 3
log 81 = x
3^x = 81
x = 4
log3 (81) = 4
2007-12-11 01:56:51 · answer #1 · answered by Como 7 · 2⤊ 0⤋
Log3 81
2016-12-29 07:52:28 · answer #2 · answered by ddene 4 · 0⤊ 0⤋
METHOD 1: what you see here is the same thing as log base 3 of 3^4. you can put this into exponential form by using properties of logs and exponentials. so that means you can say log3 81=x. log3 3^4=x put in exponential form and get 3^4=3^x this is simple exponential laws, and you can see x=4. so log3 81 is 4. try it on the calculator to check. METHOD 2: so theres a sort of ''shortcut'' you can use. as previously mentioned log3 81 is equivalent to saying log3 3^4. now using properties of log you can bring the exponent 4 down to multiply to logarithm. so you end up with 4log3 3=x. now log base(a) of a is always one. this is true for all numbers so you get 4*1=x, so x=4 Hope that helps
2016-03-14 22:03:12 · answer #3 · answered by ? 4 · 0⤊ 0⤋
log3 81 means that you are solving the equation log3 81 = x.
Using the definition of a logarithm, 3^x = 81, and it becomes clear that x = 4.
Whenever you're doing logarithms, keep in mind what it actually MEANS or else you can get stuck very easily.
Hope that helps!
2007-12-10 17:10:46 · answer #4 · answered by Anonymous · 1⤊ 0⤋
log3 81
log3 (3 x 3 x 3 x3)
=4
2007-12-10 17:47:25 · answer #5 · answered by Anonymous · 0⤊ 0⤋
3 ^4 = 81
log 3^4 = log 81
3 3
1 ^4 =1= Log 81:
3
So the answer is 4
2007-12-10 17:15:07 · answer #6 · answered by SGraja 4 · 0⤊ 0⤋
Expand Log Calculator
2016-10-01 04:17:18 · answer #7 · answered by hodgkiss 4 · 0⤊ 0⤋
log (base 3) of 81 = x ..... then,
3^x = 81 , so x = 4
3^4 = 3*3*3*3 = 9*9= 81
***********************
to change ... log ( base x) Y = N ,
use ---> x ^ N = Y
2007-12-10 17:10:06 · answer #8 · answered by tigerrr 3 · 1⤊ 0⤋