Vlad is playing on a swing set.His horizontal distance D(t) (in m) from the center (where being behind the center means a negative distance) as a function of time t (in seconds) can be modeled by a sinusoidal expression of the form a⋅cos(b⋅t)+d.At t=0, when he pushes off, he is 1m behind the center, which is as far back as he goes. The swing reaches the center 6π seconds later.Find D(t).t should be in radians.D(t)=□
Q. Vlad is playing on a swing set.His horizontal distance D(t) (in m) from the center (where being behind the center means a negative distance) as a function of time t (in seconds) can be modeled by a sinusoidal expression of the form a⋅cos(b⋅t)+d.At t=0, when he pushes off, he is 1m behind the center, which is as far back as he goes. The swing reaches the center 6π seconds later.Find D(t).t should be in radians.D(t)=□
Identify Amplitude: Identify the amplitude of the sinusoidal function.The amplitude a is the maximum distance from the center, which is given as 1m behind the center at t=0.Therefore, a=1.
Determine Horizontal Shift: Determine the horizontal shift d of the sinusoidal function.Since Vlad starts 1m behind the center and that is the farthest point, the horizontal shift d is 0.
Determine Period: Determine the period of the sinusoidal function.We know that the swing reaches the center (π/6) seconds later, which is a quarter of the period of a cosine function. To find the full period T, we multiply this time by 4.T=(π/6)×4=(2π/3) seconds.
Calculate Value of b: Calculate the value of b, which is related to the period of the sinusoidal function. The period T is related to b by the formula T=b2π. We have T=32π, so we can solve for b: 32π=b2π Cross-multiply to solve for b: b⋅32π=2πb=32π2πb=3.
Write Sinusoidal Function: Write the sinusoidal function for D(t). We have a=1, b=3, and d=0. Since Vlad starts 1m behind the center, we use a cosine function that starts at its maximum value. The function is: D(t)=acos(b⋅t)+dD(t)=1cos(3⋅t)+0D(t)=cos(3⋅t).
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