Is it okay to plot a quadratic graph using only the intercepts as guidance? or should you plot many coordinates?i know its kind of an idiotic question ..but i really need to know

Asked on by jasseb

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samhouston | Middle School Teacher | (Level 1) Associate Educator

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The intercepts do not provide enough guidance to plot a quadratic graph.  At the very least, you need the intercepts and the vertex.  If you know the vertex, then you can draw a vertical line of symmetry and use the intercepts as guides.  However, you should plot more coordinates if you can, preferrably in pairs with matching y-coordinates.  This will show the symmetry of the parabola. 

I require my students to plot the following coordinates:

*  both intercepts

*  the vertex

*  3 points on the left side of the line of symmetry and 3 cooresponding points on the right side of the line of symmetry.

I know many teachers who vary from me on the last requirement, but every teacher expects the intercepts and the vertex to be plotted.

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