The volume of water a spherical tank can hold is given by the next formula:

, where:

● V is the water volume inside the tank in

● R is the radius in , and

● h is the level of water, measured from the bottom of the tank (in ).

I need to find out, using bisection and Newton-Raphson iterations, what the level of water has to be in order to get of water from a radius tank.

So basically, what i've done is find the value of within the formula, and apply bisection to the resulting equation. But here's the problem. The resulting formula is a 3º degree formula, so i get 3 roots (obviously bisection gives me just one, depending on the initial interval).

So the three roots are (aprox.):

●

●

●

Thanks in advance.

P.S.: I'm using scilab as my numerical analysis software.