The graph of a sinusoidal function has a minimum point at (0,10) and then has a maximum point at (2,−4). Write the formula of the function, where X is entered in radians.
Q. The graph of a sinusoidal function has a minimum point at (0,10) and then has a maximum point at (2,−4). Write the formula of the function, where X is entered in radians.
Identify Amplitude: Identify the amplitude of the sinusoidal function.The amplitude A is half the distance between the maximum and minimum values of the function. The maximum value is −4 and the minimum value is 10, so the amplitude is (10−(−4))/2=14/2=7.
Determine Vertical Shift: Determine the vertical shift D of the sinusoidal function.The vertical shift is the average of the maximum and minimum values. So, D=(10+(−4))/2=6/2=3.
Calculate Period: Calculate the period T of the sinusoidal function.Since the function goes from a minimum at x=0 to a maximum at x=2, half of the period is 2. Therefore, the full period T is 2×2=4 radians.
Find Horizontal Shift: Find the horizontal shift C of the sinusoidal function. Since the minimum occurs at x=0, the horizontal shift C is 0.
Determine Reflection: Determine the reflection of the sinusoidal function.Since the function goes from a minimum to a maximum as x increases, it is a reflection of the standard sine function. This means we will use a negative amplitude.
Write Sinusoidal Function: Write the formula of the sinusoidal function.The general form of a sinusoidal function is y=A⋅sin(B(x−C))+D, where B=T2π. Since we have a reflection, A is negative. Plugging in the values we have:A=−7, B=42π=2π, C=0, and D=3.So the formula is y=−7⋅sin(2πx)+3.
More problems from Coterminal and reference angles