HP 33s Scientific manual When Solve Cannot Find a Root, 8More about Solving

Now, solve to find the root.

Keys:

Display:Description:

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2.7

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Your initial guesses for the root.

Selects Equation mode; displays the equation. No root found for f(x). f(x) is relatively large.

When SOLVE Cannot Find a Root

Sometimes SOLVE fails to find a root. The following conditions cause the message  ! :

„The search terminates near a local minimum or maximum (see figure a, below). If the ending value of f(x) (stored in the Z–register) is relatively close to zero, it is possible that a root has been found; the number stored in the unknown variable might be a 12–digit number very close to a theoretical root.

„The search halts because SOLVE is working on a horizontal asymptote—an area where f(x) is essentially constant for a wide range of x (see figure b, below). The ending value of f(x) is the value of the potential asymptote.

„The search is concentrated in a local "flat" region of the function (see figure c, below). The ending value of f(x) is the value of the function in this region.

D–8More about Solving