# Day 84: Cool Polar Graphs

Today in Precalculus, my students finished their exploration of polar graphs.  One of the nice things about the Nspire is the color aspect: each relationship is graphed with a different color.  Here a student was looking at the equation: r²=a²·cos(2θ).  Although it is hard to see, they were trying different values for a and exploring how to graph when the equation needs to be in the form r(θ) not r².  Great discussions!

After students finished yesterday’s exploration today, I gave them a graph and asked if they could figure out the equation I used to get the graph.  I asked them to see what would happen when they try equations different than the one’s they had already explored.  This led to other types of graph.  Below is one of the graphs they tried to get the one I had given (not the same one).  Thinking ahead, this could be a great lead in to comparing the rectangular equation to the polar equation.

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Posted on January 14, 2015, in Uncategorized and tagged , , . Bookmark the permalink. Leave a comment.