Question 66162
y=3Sin (x-pi/3)
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I'm not sure what you mean by "key" points but
here are a few points.
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If x=pi/3, y=3sin0=0; this is one point where the curve crosses the x-axis.
If x-(pi/3)=pi/2, x=pi/3+pi/2=(5/6)pi, y=3sin(pi/2)=3; this is the peak
point of the curve.
If x-pi/3=(3/2)pi, then x=pi/3+(3/2)pi, x=[(2+9)/6]pi=(11/6)pi
So if x=(11/6)pi y=-3; this is the lowest point of the curve
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Comment: The function has Period = 2pi so you can find as many
additional points as you wish.
Cheers,
Stan H.