# Isosceles Tutorial: Bisecting a Line Traditionally

Many geometry techniques require you to bisect a line. In this tutorial you will learn how to find the midpoint and perpendicular bisector of a line. First, ensure that Shows Intersections is turned on in the Canvas pane of the Settings.

1. Create a point to start the line.

2. With the Line Tool selected, drag from the point to create the line to bisect. (Obviously, you will not need to do this if you already have a line to bisect!)

3. Select the Arc tool. The compass should appear in the middle of the screen.

4. Move the compass to point A by dragging the center handle. Drag the compass arm to rotate it to the position shown.

5. First tap the pencil icon to switch to the light pencil (for intermediate measurements). Drag the outer handle of the compass up the circle to draw an arc. Then rotate the compass arm down, and draw another arc.

6. Move the compass to point B and repeat.

7. Choosing the Line tool will hide the compass (any tool will do, but we need the Line tool), showing your arcs:

8. Draw a line between the intersections of the pairs of arcs. This is the perpendicular bisector, and its intersection with the original line is the midpoint of line AB.

9. To make the bisector longer, tap and hold on it, tap again to show the menu, then tap Info in the menu. Turn on Extends. Now pick any two points on the line, connect them, and delete the original line.

# My Grapher Tutorial: Tangent Lines

You can use My Grapher to calculate a line tangent to a curve at a given point. Note: In this tutorial, “iPhone” refers to either an iPhone or an iPod touch.

1. iPad: Tap the + button and type in an equation for a curve. iPhone: Tap the list icon, then tap the + button to type in an equation for a curve.

2. If you graphed the equation shown above, you should get a graph like this:

3. iPad: Tap the gear icon, then tap Values. Choose Calculus from the two tabs at the top. iPhone: Tap and hold the graph, then tap Function Tool. Choose Calculus from the two tabs at the bottom. The options should look like this:

4. Tap X Value to choose which point the line should be tangent to. On iPhone, type the number in with the number keyboard.

5. Tap Done, and an equation should appear below the X Value option. Tap the equation to graph it.

# My Grapher Tutorial: Polynomials

My Grapher includes powerful tools to help you analyze polynomials. In this tutorial, we’ll enter a polynomial, trace its graph, and find zeros, minima, and maxima.

1. To enter a function in My Grapher, (iPhone) tap the list icon to open the Equation editor. Then tap the + button.

2. Use the function keyboard to enter the polynomial. Powers can be typed using the caret (^) symbol.

3. To trace the graph, tap the graph (or tap and hold on iPhone) and choose Trace Mode. Drag your finger across the graph to find the value at that point.

4. Finally, you can get the exact value of a zero or local minimum or maximum. On iPad, tap the gear icon and choose Show Notable Points. On iPhone, tap and hold the graph and choose Points. Dots will appear on the graph showing the notable points. Tap one to view its coordinates.

# My Grapher Update 3.1

My Grapher/My Grapher HD 3.1 is now available as a free update on the App Store!

In the new version, you can tap and hold on a function in the Equations editor to perform various actions on it, such as finding a best fit line of a data set or editing attributes of a graph. You can now edit the line thickness, line dash and visibility of equations. Also, you can edit the shape of data points and whether they should be connected.

My Grapher 3 introduced a brand-new user interface with new equation typesetting, new notable points, and even a new color picker.