A common mathematical problem involves finding the solution to an
equation. For example, to determine the solution to the
equation , make sure that your calculator is in radian
mode, then push the following keys:
2pt . This opens the solve menu. The Solve
equation option should be highlighted. Push . The
equation field should be highlighted. Enter either or
. Without the equals sign the HP48G/GX will set the expression
equal to zero, and then solve for the variable. Notice that the
variable *x* now has its own field. Enter a guess for the value of the
solution in the X field. After doing so, be sure to highlight the
field X, which is the variable whose value we seek.
Now push . The number
is displayed in the variable field. If we return
to the standard screen , we see that this value has
been tagged as *x*, and placed on the stack were it is available for
use in another calculation.

We may also use this program to numerically solve a single equation in more than one unknown for one of the unknowns. For example lets solve the equation . The HP48G/GX cannot solve for x as a function of y, but if we specify a particular y value, it can solve for the corresponding x value. Try this for y=2. There are three solutions. Which one the HP48G/GX calculates is determined by your initial guess. Try x = 0.2, 0.7, and -2.0. Be sure to highlight the X field before you push solve.

We determined that there were three solutions by plotting the function . From the graph we determined approximate locations of the zeros of the function.

Thu Mar 21 09:53:31 CST 1996