How do you find the domain of #f(x)= (4x)/ sqrt(x-4)#?

1 Answer
Nov 6, 2015

Domain = (4, #oo#)


When looking for domain, it is the x values that exist from negative infinity to positive infinity. For this equation, if you plug in any number where x#<=#4, we got either a negative number or #sqrt(0)#, both of which do not exist. However any value x > 4, the denominator gives us a real value. Because of this, x exists from 4 to #oo#. You use a parenthesis next to 4 and not a bracket because 4 is not included in the domain.