# Logarithm

• January 29th 2013, 12:56 PM
darence
Logarithm
One more problem:

Find all $k \in R$ so that inequalities $log_{(x-1)^2}(x+5)^4\geq1$ and $log_{x+k}(x+3)\leq1$ have no mutual solutions.
• January 29th 2013, 03:55 PM
chiro
Re: Logarithm
Hey darence.

Can you show us what you have tried (Hint: try expanding the definitions using log laws for change of base and powers and get an expression with k on one side of the inequality)?
• January 30th 2013, 03:03 AM
darence
Re: Logarithm
That's my biggest problem. I don't know where to start from with this problem
• January 30th 2013, 01:38 PM
chiro
Re: Logarithm
Hint: log_a(x) = ln(x)/ln(a) [Change of Base Rule] and ln(a^x) = x*ln(a)