Question

f(x) = −log5 x
On what interval(s) is f(x) > 0? On what interval(s) is f(x) < 0? (Enter your answers using interval notation. If there are no such intervals, enter NONE.)
f(x) > 0:
f(x) < 0:

How do I figure this out?

Answer 1

Log(x) is negative for 0 < x < 1
Log(x) is positive for 1 < x
Log(1) = 0
Log(x) is undefined for x = 0 and x < 0

Answer 2

So (1,infinity) and (0,1)? I've tried putting that in but it won't accept my answer.

Answer 3

@KenLJW

Answer 4

f(x) = −log(5 x)
f(x) = log[1/(5 x)]
f(x) < 0 x > 1/5
f(x) > 0 0 < x < 1/5

Answer 5

Neither of those work, though...

Answer 6

for equation as given this is the answer.
are you sure its not -xLog5

Answer 7

Postive. Copied it straight off the screen. I'll even screencap it for you.

Answer 8

I actually just figured it out... our book tells us that log functions should be inverses for exponentials, so log5x should be the inverse of 5^x. What I was doing was -5^x, not 5^-x... so I just got the answer!

Answer 9

I see your error f(x) = Log 5 of x
convert logarithm