3-6-3

Using the Sketch Menu

uTo draw a line tangent to a graph

Example: To draw a line tangent to the graph y = x2 – x – 2 when x = 1

(1)In line y1 of the Graph Editor window, input and save y = x2 – x – 2.

(2)Tap $ to graph the function.

(3)Tap [Analysis], [Sketch], and then [Tangent].

•This displays the crosshair pointer along with its corresponding coordinate values.

(4)Press 1.

•This displays a dialog box for inputting the point of tangency x-value, with 1 specified as the point.

(5)Tap [OK].

•This closes the dialog box and moves pointer to the location you specified in step (4).

(6)Press E.

Tip

•Instead of inputting coordinate values in steps (4) and (5), you can use the cursor key or the graph controller arrows to move the pointer to the point of tangency on the Graph window.

uTo draw a line that is normal to a graph

The procedure for drawing a line that is normal to a graph is virtually identical to the procedure “To draw a line tangent to a graph”, above. The only difference is in step (3), where you need to tap [Analysis], [Sketch], and then [Normal] instead of [Tangent].

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