# combine graphs and equations

## Introduction

Exercises for which drop-down lists are very practical to are combination exercises. In next applet you have to combine four graphs and their equations.

## How it is done?

• four functions - Create four functions, save each graph as a picture and insert the four pictures. - Add the texts A, B, C and D under the four pictures to identify the graphs. - Create four texts with the equations of the four functions, sorted differently than the graphs.
• four lists - Create list1, list2, list3 and list4 as `{"", "A", "B", "C", "D"}` - Select in the Basic tab of the Properties the option `Draw as drop-down lists` to show them.
• four answers: Create - `ans1 = SelectedIndex(list1)` and likewise ans2, ans3 and ans4
• Control: Define the dynamic colors if the drop-down list according to the right combinations - The color should turn Red if the selection is not blank and not equal to the right function. - The color should turn Green if the selection fits the function. Since the equation f1 fits to D (= the fith option of the list) we get for the first list: ` ````Red: If((ans1 ≠ 1) ∧ (ans1 ≠ 5), 1, 0) Green: If(ans1 ≟ 5, 0.7, 0) Blue: 0```
• Button: Create a button to reset all lists to their initial position (= blank) with the script ```SetValue[list1,1] SetValue[list2,1] SetValue[list3,1] SetValue[list4,1]```