Graph of a sinusoidal wave at a fixed position

[MyNewPony]

Homework Statement

A sound wave is described by D(y,t) = (0.02mm)sin[(8.96 rad/m)y + (3140 rad/s)t + pi/4 rad)], where y is in metres, and t is in seconds.

Draw a displacement-versus-time graph D(y=1.00m,t) at y= 1.00 m from t= 0 s and t= 4 ms.

Homework Equations

D(y,t) = (0.02mm)sin[(8.96 rad/m)y + (3140 rad/s)t + pi/4 rad)]

The Attempt at a Solution

I tried doing the graph (see figure attached), but apparently it's wrong. By 'fixed' position, it means that I must plug in 1.00 m into y for the entire time interval (0 to 4ms), correct? If that's the case, then all the points on the graph should be right. Can someone explain what I'm doing incorrectly?

 

[MyNewPony]

Ah, my bad. I jumped the gun and skipped the points in between each tick.

 

[amohammadi]

I got the same graph as you did. How did you figure out how to get the points in between the points you already have on your graph? Because when I plug in y=1 into the equation, I don't get the right answer.