Graphing the Tangent Function

Explore this applet by watching how it is using the Unit Circle to graph the cosine function.

Why does the graph of have x-intercepts at 90 , 270 , 450 , etc.?

Why does the graph of have maximums/minimums at 90 , 270 , 450 , etc.?

Why does the graph of have x-intercepts at 0 , 180 , 360 , etc.?

What is the period of the graph of ? Explain why that is the case.