The @ZOOM key, when pressed, produces a menu with the options: In, Out, Decimal, Integer, and Trig. Try the following exercises:

With the option In highlighted, press @@@OK@@@. The table is expanded so that the x-increment is now 0.25 rather than 0.5. Simply, what the calculator does is to multiply the original increment, 0.5, by the zoom factor, 0.5, to produce the new increment of 0.25. Thus, the zoom in option is useful when you want more resolution for the values of x in your table.

To increase the resolution by an additional factor of 0.5 press @ZOOM, select In once more, and press @@@OK@@@. The x-increment is now 0.0125.

To recover the previous x-increment, press @ZOOM —@@@OK@@@ to select the option Un-zoom. The x-increment is increased to 0.25.

To recover the original x-increment of 0.5 you can do an un-zoom again, or use the option zoom out by pressing @ZOOM ˜@@@OK@@@.

The option Decimal in @ZOOM produces x-increments of 0.10.

The option Integer in @ZOOM produces x-increments of 1.

The option Trig in produces increments related to fractions of π, thus being useful when producing tables of trigonometric functions.

To return to normal calculator display press `.

Fast 3D plots

Fast 3D plots are used to visualize three-dimensional surfaces represented by equations of the form z = f(x,y). For example, if you want to visualize z = f(x,y) = x2+y2, we can use the following:

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HP 49g manual Fast 3D plots