In this blog post, we will be discussing a sound wave and the graph of its negative 3-sine function. A sound wave is an oscillation in pressure that propagates through air, water or other medium. The sine function is a mathematical way to describe periodic waves like those seen on ocean waves; it can also model simple harmonic motion for example, swinging a pendulum back and forth. When you plot the graph of y=-3 sin x, you get an interesting pattern with one peak around where x = pi/4 radians (45 degrees) and two peaks at +/- pi/2 radians (90 degrees). A sound wave and the graph of its negative sine function is often used in physics to model a plucked or struck stringed instrument, like a guitar. It’s also useful for modeling other types of periodic waves such as ocean waves. The two peaks at +/- pi/√- radians are called anti-nodes; they represent points on opposite ends of an oscillating medium that do not move relative to each other during oscillation. If you were trying to find out where along the x axis these nodes occur then your equation would be y=-(-pi) sin(x). To make this easier we can change it so there is only one – sign instead: (-pi)/sin(x)). Now you have simplified your