The 9860’s Solver gives the “wrong” solution to equations

At times when using the Solver of the 9860, a solution to the equation that differs from the one expected is obtained. This arises when the equation being solved has more than one solution, and the user is interested in one solution in particular. A simple example is shown below, with an expected solution of 60 degrees.

Upon pressing SOLV, a solution other than 60 degrees is obtained

This value of x does in fact solve the equation, but the user was probably looking for the answer between 0 and 90 degrees.

To resolve this, the user can specify the range of x-values within which the Solver will search for a solution. This is done using the Lower and Upper bounds:

Note: There is no way for the Solver to obtain more than one solution at a time. If multiple solutions need to be ‘seen’ simultaneously, other functionality is required, like the use of y