The graph of a sinusoidal function has a minimum point at (0,3) and then intersects its midline at (5π,5).Write the formula of the function, where x is entered in radians.
Q. The graph of a sinusoidal function has a minimum point at (0,3) and then intersects its midline at (5π,5).Write the formula of the function, where x is entered in radians.
Determine Amplitude: Determine the amplitude of the function.Since the graph has a minimum point at (0,3) and intersects its midline at a higher value, the midline value is the average of the maximum and minimum. The given midline value is 5, and the minimum value is 3, so the amplitude (A) is the difference between the midline and the minimum value.A=Midline−MinimumA=5−3A=2
Identify Vertical Shift: Identify the vertical shift D. The midline value also represents the vertical shift of the function. Since the midline is at y=5, the vertical shift D is 5. D=5
Calculate Period: Calculate the period of the function.The function intersects its midline at (5π,5), which is a quarter of the period away from the minimum point at (0,3). Therefore, the period T is four times the x-value of the midline intersection.T=4×(5π)T=20π
Find Value of B: Find the value of B using the period.The period T is related to B by the formula T=B2π. We can solve for B using the period we found.T=B2π20π=B2πB=20π2πB=101
Determine Phase Shift: Determine the phase shift C. Since the minimum point is at (0,3), and we know that the cosine function starts at a maximum, we will use a sine function which starts at a minimum when there is no phase shift. Therefore, C=0. C=0
Write Equation: Write the equation of the function.We have determined the amplitude A, the vertical shift D, the value of B, and the phase shift C. The general form of a sinusoidal function is f(x)=A⋅cos(Bx+C)+D or f(x)=A⋅sin(Bx+C)+D. Since we are using a sine function that starts at a minimum, we will use the sine form.f(x)=A⋅sin(Bx+C)+Df(x)=2⋅sin(101x+0)+5
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