SO, A function $f(x)$ is given to me and but the initial intervals are not given. I need to find the root of the equation using Bisection method.
Sometimes when I randomly guess the initial interval which obeys $f(a)·f(b)<0$ (where $a$ and $b$ are initial intervals) the no of iterations gets ridiculously large, sometimes 10-15 iterations. Since, I'll only have 3 hours in examination, I don't want to waste too much time on a single question. I know that the closer to the actual root my initial guesses are the lesser the no of iterations will be required.
Is there any quick way to calculate the root using calculator. I have a casio fx-991ES. I have tried using the solve equation function but for 2nd and 3rd degree equations calculator gives 2 and 3 roots which is what it is supposed to do. But since I'll be finding only one root with bisection method, I am confused on which root to take.