Show that the function F( x)=∫(from x to 3x)1/t dt is constant on the interval (0, +∞).

Okay so I'm not sure if I should use the FTOC Part 1 or something else but this question is just really confusing.
I asked my brother and he said I should just solve the integral but all I keep getting is:
F(x) = ln|3x| - ln|x|
It feels as though I'm forgetting the chain rule or something but I don't know how to implement it.
Even if I wanted to find F'(x) or something else, the question itself doesn't make sense to me. What is it asking for? Thank you.

1 answer

ln(3x)-ln(x) = ln(3x/x) = ln3
is constant