Pre-Cal Help PLZZZ?

Question

The problem is Sketch one period in the positive direction and one in the negative direction for each function.

1. y=3sinx
2. y=3sin2x
3. y=3sin2x+1
4. y=3sinx/2+1
5. y=3sinx/2-1
6. y=5sin(x-pi)
7. y=5sin(x+pi)
8. y=1/3cos(x+pi/2)

Can some please give me the x and y values for all of these, or tell me how to do these problems. Do i have to graph these. I just need to know how to do these. :(

Answer 1

You know that the sin graph is a wave, right? Just get values of y for different values of x, then you can sketch the graph. Here, I will help you with #1:

You know (or should know) the following, as this is very basic trig info. If you don't know it, then I suggest you memorize it as you will need it all year long!

sin 0 = 0

sin (pi/2) = 1

sin (pi) = 0

sin (3pi/2) = -1

sin (2pi) = 0 <-- this is where the graph starts repeating

So you can determine the following points for your graph, then just connect the points with your wavy sine graph --- don't forget to fill in the graph for the negative side of the number line as well:

(0,0) , (pi/2,3) , (pi, 0) , (3pi/2,-3)

Is this enough help to get you on your way?