How do I graph y = 2 - sin(3x - ∏/5) without a calculator?

AI Thread Summary
To graph the function y = 2 - sin(3x - π/5) without a calculator, start by identifying the amplitude, period, and phase shift. The amplitude is 1, the period is 2π/3, and the phase shift is π/15. The graph will be reflected across the x-axis, and the x-axis can be scaled by π/30 to plot key points. Begin the graph at the phase shift of π/15 and calculate subsequent points by adding π/6. Understanding these transformations is crucial for accurately graphing the function.
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Homework Statement


I have to graph this function without a calculator, and I'm not sure how to scale the x axis.
y = 2 - sin(3x - ∏/5)

Homework Equations


y = Asin(Bx + C)
Period = 2∏/B
Phase Shift = -C/B

The Attempt at a Solution


I know that the graph will be reflected across the x axis
Amplitude: 1

Period: 2∏/3
Period divided by four = ∏/6

Phase Shift: (∏/5)/3 = ∏/15

My professor had told us to graph with a phase shift, you add the period/4 four times like this:

∏/15 + ∏/6 = 7∏/30
7∏/30 + ∏/6 = 12∏/30 or 2∏/5
12∏/30 + ∏/6 = 17∏/30
17∏/30 + ∏/6 = 21∏/30 or 11∏/15

I'm supposed to start the graph at the phase shift, ∏/15, but I don't know how to scale the rest of the x-axis. How do I get to 7∏/30 on the numberline from ∏/15? Gosh I feel so dumb ):
 
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Ohhhhhhhhhhhhhhhhhhhhhhhhhh, I scale it by ∏/30 don't I? Cue facepalm.
 
No, you don't. 3x- \pi/5= 3(x- \pi/15).
 
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