SOLUTION: If f(x) = log2x, find f(16) 16=log 2x 2^16 =65,536 is this right

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: If f(x) = log2x, find f(16) 16=log 2x 2^16 =65,536 is this right      Log On


   



Question 253217: If f(x) = log2x, find f(16)
16=log 2x
2^16 =65,536
is this right

Found 2 solutions by drk, Earlsdon:
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
I assume you mean the 2 is the base.
F(x) = log_2(x)
We want to find the value of F when x = 16. Where you see x, replace it with 16.
F(16) = log_2(16)
what is the value of log_2(16)?
2^y = 16
y = 4.

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Not quite!
If f%28x%29+=+Log%5B2%5D%28x%29 find f%2816%29
Recall that the definition of the logarithm of a number is the "power" to which the "base" must be raised to equal that number. Or Log%5Bb%5D%28x%29+=+y which can be expressed as: b%5Ey+=+x
In this problem, the 'base' is given as 2, and to find f(16) you must replace the x in the f(x) of the problem with 16, so now you have:
f%2816%29+=+Log%5B2%5D%2816%29
Let's rewrite the problem a bit replacing f%2816%29 wth y:
Log%5B2%5D%2816%29+=+y, then according to the above definition, we can write this as (Log%5Bb%5D%28x%29+=+y--->b%5Ey+=+x:
2%5Ey+=+16 Substitute 16+=+2%5E4
2%5Ey+=+2%5E4 Now since the bases are equal, the exponents must be equal, so...
y+=+4 but y+=+f%2816%29 so...
highlight%28f%2816%29+=+4%29