# Thread: y=2sin3x Reflection?

1. ## y=2sin3x Reflection?

Help is greatly appreciated. Thank you in advance.

The graph of $y=2sin 3x$ is reflected in the x-axis.

a) Sketch a graph of one period of the original curve.

b) Sketch a graph of the curve after the reflection.

c) Write an equation for the new curve.

2. Originally Posted by ThaBeretta
Help is greatly appreciated. Thank you in advance.

The graph of $y=2sin 3x$ is reflected in the x-axis.

a) Sketch a graph of one period of the original curve.

b) Sketch a graph of the curve after the reflection.

c) Write an equation for the new curve.

$y=2sin 3x$ is the same as $y=sin(x)$ with the amplitude doubling and the period being one third the distance along the x-axis

The reflection is the graph redrawn around the same central point the x-axis but flipped upside down. These things are really hard to explain in such a forum, it would be alot easier with pen and paper!

The equation is: $y=-2sin 3x$

3. I kind of understand what you're saying. Is there any way you'd be able to sketch one or both graphs and scan them onto the computer? I know it's a bit much to ask for, but this is really hard to explain and understand over text.

4. I have attached an excel file

5. That's awesome! Now I see what you mean by the wave flipped upside down. Thanks again for your help and patience!

6. I'm sorry, but one last thing. I see how the graphs are created, but how would I sketch them? The problem wants only one period. Could I just graph them from 0 to 2pi? If so, how would I fit three sin curves in?

7. Originally Posted by ThaBeretta
I'm sorry, but one last thing. I see how the graphs are created, but how would I sketch them? The problem wants only one period. Could I just graph them from 0 to 2pi? If so, how would I fit three sin curves in?
You are correct in saying three curves would fit between 0 and 2pi.

I would draw an x-axis from 0 to 2 pi and cut it evenly into 3. Then draw the graphs into these intervals. Each repetition should end at pi/3,2pi/3 and 2pi.

Make sense?!

8. Yeah, I think I got it. Thanks for all of your help and time.