How do you graph two cycles of y=-0.5tan(2theta)?

1 Answer
Mar 20, 2018

A = -.5; " " B = 2; " period " = pi/2

Explanation:

Given: y = -0.5 tan(2 theta)

To graph the function you need to figure out the amplitude, period, phase shift and vertical shift.

The standard form is y = A tan (Bx - C) + D

where A = amplitude; " "period = pi/|B|
phase Shift = C/B; " vertical shift" = D

From the given function: A = -0.5; " period" = pi/2
There is no vertical or phase shift.

From the graph: y = tan x note the direction.
graph{tan x [-10, 10, -5, 5]}

Since the given function has a negative value, the function is flipped about the y-axis.

The function is center at (0,0).

Vertical asymptotes are at half a period on each side of (0,0).

1/2 period about (0,0) = +-1/2 * pi/2 = +-pi/4

The next vertical asymptote is one period away: pi/4 + pi/2 = (3 pi)/4

The x-intercepts are at (0,0), (0, pi/2), ...

Graph: y = -0.5 tan (2 theta):
graph{-0.5 tan(2x) [-3.897, 3.9, -1.95, 1.947]}