Graphing Tangent Function
The trigonometric ratios can also be considered as functions of a variable which is the measure of an angle. This angle measure can either be given in degrees or radians . Here, we will use radians.
Since , 
the tangent function is undefined when cos x = 0. Therefore, the tangent function has a vertical asymptote whenever cos x = 0.
Similarly, the tangent and sine functions each have zeros at integer multiples of 
because tan x = 0 when sin x = 0.
The graph of a tangent function y = tan x is looks like this:
Properties of the Tangent Function, y = tan x.
Domain: 
, where n is an integer.
y -intercept: (0, 0)
x -intercept: 
, where n is an integer.
Period:
Symmetry: origin (odd function)
Amplitude and Period of a Tangent Function
The tangent function does not have an amplitude because it has no maximum or minimum value.
The period of a tangent function, y = a tan bx , is the distance between any two consecutive vertical asymptotes.
Period = 
Also see Trigonometric Functions.
