# Thread: graphing sin x functions

1. ## graphing sin x functions

Hello. I need help graphing y = 4 sin (-2x). Also what is the amplitude, period and phase shift. Thank you!

2. do you know the graph of sinx if you know it that will be easy to graph 4sin(-x)
first

-1<=sinx <=1 right so -pi/2 < x < pi/2 right this is a half wave with tall one unit just

but 4sin(-x) tall of the half wave would be 4 not 1

see this

3. If you have a sinusoid in the form of $f(x) = a\:\sin [b(x - h)] + k$ , then the amplitude is $|a|$, the period is $\frac{2\pi}{|b|}$ , and the phase shift is $h$ . ( $k$ represents the vertical translation.)

So in your problem the amplitude is 4, the period is π, and the phase shift is 0. In addition, since there is a negative sign in front of the 2, there is a reflection on the x-axis.

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