I need to apply the bisection method to find the possible roots of the homogeneous equation, $f(x) = 0$, I know how to do the method because it is simple.
The problem is that I need to start from an interval in order to apply this method. So, obviously, the smaller the interval, the less iterations I have to perform.
But I don't know how to find that interval. My Numerical Calculation teacher does something about derivatives, but I'm not sure.
For example, could you do it for the next $f(x)$?
$$f(x) = e^x+3x^4-7x^2$$