Find an equation for a sinusoidal function that has period 2Ο, amplitude 1, and contains the point (0,β1). Write your answer in the form f(x)=Acos(Bx+C)+D, where A, B, C, and D are real numbers.
Q. Find an equation for a sinusoidal function that has period 2Ο, amplitude 1, and contains the point (0,β1). Write your answer in the form f(x)=Acos(Bx+C)+D, where A, B, C, and D are real numbers.
Period Calculation: We are given the period of the sinusoidal function as 2Ο. To find the value of B, which affects the period of the cosine function, we use the formula for the period of a cosine function, which is (2Ο)/B.
Calculation of B: Since the period is 2Ο, we set up the equation (2Ο)/B=2Ο and solve for B.(2Ο)/B=2ΟB=(2Ο)/(2Ο)B=1
Amplitude and Shift: Next, we know the amplitude A is given as 1. This means the function will have a maximum value of 1 and a minimum value of β1. Since the point (0,β1) is on the graph, this indicates that the cosine function must be shifted vertically or horizontally to pass through this point.
General Cosine Function: The general form of the cosine function is f(x)=Acos(Bx+C)+D. Since we have A=1 and B=1, we can substitute these values into the equation to get f(x)=cos(x+C)+D.
Determining Values of C and D: Now we need to determine the values of C and D. Since the function passes through the point (0,β1), we can substitute x=0 and f(x)=β1 into the equation to find D.β1=cos(0+C)+DSince cos(0)=1 for any value of C, we have:β1=1+DD=β1β1D=β2
Correction for Value of D: However, we have made a mistake in the previous step. The amplitude of the function is 1, so the maximum and minimum values of the function are 1 and β1, respectively. Since the point (0,β1) is on the graph and the amplitude is 1, this means that the cosine function is at its minimum value when x=0. Therefore, the value of D should be β1, not β2, because the vertical shift D must bring the minimum value of the cosine function down to β1.
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