# sine graph equation

Figure 7 shows that the cosine function is symmetric about the y-axis. Purplemath. See the graph on the right to find out what happens when y= sin x is overlaid by y = sin (x-3). We can see that the graph rises and falls an equal distance above and below $y=0.5$. Sketching the height, we note that it will start 1 ft above the ground, then increase up to 7 ft above the ground, and continue to oscillate 3 ft above and below the center value of 4 ft, as shown in Figure 24. Copyright © 2005, 2020 - OnlineMathLearning.com. Let’s begin by comparing the equation to the general form $y=A\cos(Bx−C)+D$. These lessons are compiled to help Algebra 2 students find the equations of sine and cosine graphs. If $|A| < 1$, the function is compressed. Figure 20 shows the graph of the function. Although we could use a transformation of either the sine or cosine function, we start by looking for characteristics that would make one function easier to use than the other. The waves crest and fall over and over again forever, because you can keep plugging in values for. Since A is negative, the graph of the cosine function has been reflected about the x-axis. where t is in minutes and y is measured in meters. Sketch a graph of the height above the ground of the point P as the circle is rotated; then find a function that gives the height in terms of the angle of rotation. Sketch a graph of the function, and then find a cosine function that gives the position y in terms of x. The graph could represent either a sine or a cosine function that is shifted and/or reflected. Sketch a graph of the y-coordinate of the point as a function of the angle of rotation. The following steps show you how to construct the parent graph for the sine function, Keep in mind that because all the values of the sine function come from the unit circle, you should be pretty comfy and cozy with the unit circle before proceeding. Assume the position of y is given as a sinusoidal function of x. Again, we determined that the cosine function is an even function. Determine the formula for the cosine function in Figure 15. Let’s use a cosine function because it starts at the highest or lowest value, while a sine function starts at the middle value. We can see from the equation that A=−2,so the amplitude is 2. We have included a tool that will plot the sine graph Graph variations of y=cos x and y=sin x . The graph of $y=\sin x$ is symmetric about the origin, because it is an odd function. Also, the graph is reflected about the x-axis so that A=0.5. Determine the midline, amplitude, period, and phase shift. Step 1. Step 1. Because the graph of the sine function is being graphed on the x–y plane, you rewrite this as f(x) = sin x where x is the measure of the angle in radians. When you graph lines in algebra, the x-intercepts occur when y = 0. Determine the phase shift as $\frac{C}{B}$. Both y=sin⁡(x){\displaystyle y=\sin(x)} and y=cos⁡(x){\displaystyle y=\cos(x)} repeat the same shape from negative infinity to positive infinity on the x-axis (you'll generally only graph a portion of it). The function is already written in general form. $y=A\sin\left(Bx-C\right)+D$, $y=A\cos\left(Bx-C\right)+D$. The b-value is the number next to the x-term, which is 3. Write a formula for the function graphed in Figure 18. two possibilities are: $y=4\sin(\frac{π}{5}x−\frac{π}{5})+4$ or $y=−4sin(\frac{π}{5}x+4\frac{π}{5})+4$. Sketch a graph of $g(x)=−0.8\cos(2x)$. Figure 3. Sine functions are perfect ways of expressing this type of movement, because their graphs are repetitive and they oscillate (like a wave). midline: $y=0$; amplitude: |A|=$\frac{1}{2}$; period: P=$\frac{2π}{|B|}=6\pi$; phase shift:$\frac{C}{B}=\pi$. With a diameter of 135 m, the wheel has a radius of 67.5 m. The height will oscillate with amplitude 67.5 m above and below the center. Figure 20. Let’s begin by comparing the equation to the form $y=A\sin(Bx)$. Step 5. A function that has the same general shape as a sine or cosine function is known as a sinusoidal function. Again, we can create a table of values and use them to sketch a graph. Let’s begin by comparing the function to the simplified form $y=A\sin(Bx)$. The official math definition of an odd function, though, is f(–x) = –f(x) for every value of x in the domain. A circle with radius 3 ft is mounted with its center 4 ft off the ground. For example. period is more than 2Ï then B is a fraction; use the formula period = 2Ï/B to find the exact value. Since $|B|=|\frac{π}{4}|=\frac{π}{4}$, we determine the period as follows. The period is $\frac{2π}{|B|}$. So |A|=0.5. You can graph any trig function in four or five steps. Identify the phase shift, $\frac{C}{B}$. Writing Equation Of Sin And Cos Graph When finding the equation for a trig function, try to identify if it is a sine or cosine graph. Any value of D other than zero shifts the graph up or down. Determine the direction and magnitude of the phase shift for $f(x)=3\cos(x−\frac{\pi}{2})$. The greater the value of |C|, the more the graph is shifted. Let’s start with the midline. To find the equation of sine waves given the graph: The general equation of a sine graph is y = A sin(B(x - D)) + C