Change the focus and the directrix, all perpendicular bisectors should also change dynamically.Write PerpendicularBisector(A1, A) in cell B1 and make relative copies along column B.Write A2 + u in cell A3 and make relative copies along column A.In that way they will be shown in the spreadsheet. Place a point \(E\) on the line and make a vector \(\vec\) from \(D\) to \(E\).Remove the trace from the perpendicular bisector.Instead of the using trace you will now create a number of points on the line and a number of perpendicular bisectors. Put a trace on the perpendicular bisector and drag \(D\). Place a fourth point \(D\) on the line and create the perpendicular bisector between \(A\) and \(D\).
Make a point \(A\) and a line through two points \(B\) and \(C\). Many perpendicular bisectors can be used to show the shape of the parabola. It can be shown that this perpendicular bisector is a tangent to the parabola through \(P\). For them a parabola was a geometric object that could be defined like this: Given a line (called the directrix) and a point (called focus) a parabola is the set of points having the same distance to the point and to the line.Ī point \(P\) having the same distance to the point and to the line must lie on the perpendicular bisector of the point and some point on the line. The ancient Greeks didn't have the Cartesian coordinate system or functions. Drag the sliders to study the salaries.Select cells from two columns, then choose Create - > List of points.ĭrag the \(y\)-axis until you see the points in the graphics view. Let them start with the same salary year 0.Ĭreate a list of points for Anna and one for Bertil. Make a slider \(b\) of integer values between 0 and 100 representing Bertil's annual percentage raise of his monthly salary.Įnter year and monthly salaries for Anna and Bertil in the spreadsheet and make relative copies showing their salaries over a number of years. Make a slider \(a\) of integer values between 0 and 10,000 representing Anna's annual raise of her monthly salary in Swedish kronor. By writing such expressions in cells in the spreadsheet, you can create functions. If you write an expression using the variable \(x\), GeoGebra will create a function of \(x\).
Using the spreadsheet for objects and colors. When making relative copies, the values of the colors will also be relatively copied. In the spreadsheet you can let the color of an object depend on the value of some cell. You can write logical expressions for what colors to use, or let the color depend on some variable, hence the name dynamic colors. Here you can specify a color by giving the red, green, and blue value. If you right-click on an object to see the properties-window, there is a heading Dynamic Colors under the tab Advanced.
Geogebra classic wiki code#
If you need help writing a command, write it in the input bar of the spreadsheet to get help with code completion. You can create objects by writing commands in a cell in the spreadsheet. You can use the dollar-sign to make copies using an absolute reference.īy writing $A1, you make an absolute reference to A1 when dragging along a row.īy writing A$1, you make an absolute reference to A1 when dragging along a column.īy writing $A$1, you make an absolute reference to A1 when dragging both along a column and along a row.Ībsolute references can be used for producing a multiplication table. When A2 is dragged downwards to make relative copies, each cell vill get the value from the cell above and add one to this value.
If cell A1 contains the value 5 and A1 + 1 is written in cell A2, then the value of A1 is picked from the relative position, i.e. By dragging the filled in rectangle, you make so called relative copies. After selecing one or many cells, a filled-in blue rectangle is shown in the lower right corner of the selection. The basic feature of any spreadsheet is that you can make relative copies by dragging a cell, or by dragging many cells. Each cell is denoted by a letter (the column) and a number (the row). Move the point! Relative copiesĪ spreadsheet is a table of so-called cells. Load GeoGebra worksheet Ellipse or hyperbola.
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