## dy/dx command

The dy/dx command finds a numeric derivative, which approximates the first derivative of
an expression with respect to the x variable at a chosen value for x or at the trace cursor
location while viewing a graph.

While viewing the graph of a function, press
to view the CALCULATE menu.

Press .

If more than one function is graphed, use
to select the desired
curve. Enter the x-coordinate of the point on the curve for which the value of the
derivative is needed (or trace the curve to the approximate point) and press .
The value (or approximate value) of dy/dx at the point is displayed at the bottom of
the screen.

**Note:** The value of the derivative is found by computing the slope of the line
through the points and where
.