Let the function is y = g(x) = 3 cot (x + π/6) + 2.

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Compare the equation y = 2 + 3 cot [ 1 (x + π/6) ] with y = k + A cot [ B (x - h) ] where B > 0.

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k = 2, A = 3, B = 1 and h = - π/6.

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Period = π/B = π/1 = π.

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Horizontal translation = Phase shift = h = - π/6.

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Vertical translation = k = 2.

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For cotangent functions, there is no concept of amplitude since the range of the cotangent function is (- ∞ , ∞) or the set of all real numbers. The value of | A | is the factor by which the basic graphs are expand or contracted vertically. If A < 0 the graph will be reflected about the x - axis.

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The domain of cotangent function, y = cot (x) is - ∞ < x < ∞, where x not equal to integer multiplies of π.

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The period of y = tan x is π, so the period of y = k + A cot [ B (x - h) ] is π/b = π/(1) = π, caused by the horizontal compression of the graph by a factor of 1/b = 1/1 = 1.

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Two consecutive vertical asymptotes can be found by solving the equations B (x - h) = 0 and B (x - h) = π.

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x + π/6 = 0 ------> x = - π/6 and

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x + π/6 = π -------> x = π - π/6 -----> x = (6π - π)/6 -----> x = 5π/6.

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The two consecutive vertical asymptotes occur at x = - π/6 and x = 5π/6.

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The interval [- π/6, 5π/6] corresponds to one cycle of the graph. Dividing this interval into four equal parts produces the key points.

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one fourth of cycle is [5π/6 - (- π/6) ]/4 = (6π/6)(1/4) = π/4.

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The x - coordinates of the five key points are

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x = - 13π/3.

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x = - 13π/3 + π/2 = (- 26π + 3π)/6 = - 23π/6.

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x = - 23π/6 + π/2 = (- 23π + 3π)/6 = - 20π/6 = - 10/3π.

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x = - 10π/3 + π/2 = (- 20π + 3π)/6 = - 17π/6.

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x = - 17π/6 + π/2 = (- 17π + 3π)/6 = - 14π/6 = - 7π/3.

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Between these two asymptotes, plot a few points, including the -intercept, as shown in the table.

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First ploting the asymptotes.

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The midpoint between two consecutive vertical asymptotes is an x - intercept of the graph. The period of the function y = a tan(bx - c) is the distance between two consecutive vertical asymptotes. The amplitude of a tangent function is not defined.

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After plotting the asymptotes and the x - intercept, plot a few additional points between the two asymptotes and sketch one cycle. Finally, sketch one or two additional cycles to the left and right.

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Plot these five points and fill in the graph of the tangent function as shown in Figure.

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