Using Calculators to Sketch Graphs (Cambridge (CIE) IGCSE International Maths)

Using Calculators to Sketch Graphs

How do I draw graphs on my graphic display calculator?

• Navigate on your calculator to the Add Graphs button

  • You may need to start a new document first

  • On some models you will need to select graph mode in the menu

• Enter the equation of the function on the line f(x)=

  • This is the function,

  • On other models it may be labelled as f1(x)= or Y1:

• Press enter or EXE and the graph should appear

  • You may need to go to the menu or press the zoom button to zoom in or out

    • The "zoom - fit" button (or equivalent) automatically zooms for you on the key features

    • Other models may also have a "V-Window" menu where you can select the exact range of values to show

How do I find graph features using my graphic display calculator?

• Once the graph is drawn, go to the menu and select analyze graph (or equivalent), which gives a list of options

  • Other models may feature a G-Solv button

• Zeros (or roots): these are the x-intercepts

  • You may have to click before and after the x-intercept you require so that the calculator knows where to search

  • y-intercepts can be found without a calculator by substituting into

    • though some models do include a Y-ICEPT button which can be used

• Maximum or minimum points: these are the coordinates of the highest point and lowest point on the graph

  • You may have to click before and after the point you require so that the calculator knows where to search

  • These can be called local maxima or local minima

  • They are also referred to as turning points

    • or the vertex if talking about a quadratic graph

How do I sketch a graph in the exam from my graphic display calculator?

• Exam questions may ask you to sketch the graph on a given blank set of axes

  • You do not need to plot points exactly

    • and you do not need a table of values

  • Draw a single smooth freehand curve that copies the shape of the curve on your graphic display calculator

    • Do not use a ruler for curves!

    • Copy any key features and symmetries

• Exam questions may ask you to use your calculator to sketch an unknown function that you have not seen before

How do I create a table of values on my graphic display calculator?

• Your calculator can create tables of values for you, if needed

• Find the table function

  • Type in the graph equation (the function, f(x)=) 

  • Enter the start value (or equivalent)

    • The first x-value in the table

  • Enter the end value (or equivalent)

    • The last x-value in the table

  • Enter the step size (or equivalent)

    • How big the steps (gaps) are from one x-value to the next

  • You may have to select SET to set the above values

  • Press enter or EXE to see the table of values