gCalcD: Equation Solver

Solving One-Variable Equation f(x) = 0, Finding Roots of f(x)

By pressing the Solve f(x) = 0 button the roots (or zeros) of the function on the specified domain interval are calculated and displayed on a new window. This is equivalent to solving one variable equations. For example to solve the equation x2 - 3x + 2 = 0, just type in the left hand side and press Solve f(x) = 0 (make sure Function is selected for the Graph Type).

In most cases the graphing calculator finds all the roots on the interval very efficiently. In other cases, some roots (or solution of (f(x) =0) are not detected on the first try. This might happen when the graph of the function touches the x-axis without crossing it, for example, (x - 0.123)2 or sin(x)2.

Fortunately, the graphing calculator is able to handle these cases very accurately. Press the Try again button to find other roots that might have been missed. These two cases are handled separately for the sake of saving time for finding roots for most functions that do not need a second try especially when the domain interval is very large.

However there are trivial cases that you will find excess "roots" appear because of round off error. This happens when the graph of the function is very close to the x-axis on a sub-interval. For example, the graph of x10 is very close to the x-axis on a sub-interval about 0 which produces "unwanted roots" especially when you press Try again.

It is always helpful to look at the graphs when finding the roots of functions.