Find the roots of the function find the roots of the function when $x$ goes from $0$ to $3$?

$$f(x) = \tan(2 x) - 1$$

I tried to set $f(x)=0$ but came up with $x=28$
root of trigonometric function is not unique
Just set $f(x) = 0$, that is,

$\tan(2x) - 1 = 0 \implies \tan(2x) = 1 \implies 2x = \arctan(1) \implies x = \frac{\arctan(1)}{2} \approx 0.3927$