Question

Show that the function f(x)= integral from x to 3x 1/t ft is constant on the interval (0, positive infinity)

Answer 1

$\int\limits^{3x}_x { \frac{1}{t} } \, dt$
integrate to get
$[ln|t|]^{3x}_x=ln|3x|-ln|x|=ln| \frac{3x}{x}| =ln |3|=ln(3)$
this only is true when x>0
when x turns negative, we get -ln(3) because of math