Answer:
L(t) = 5·sin(πt) +7
Step-by-step explanation:
The middle of the oscillation of the given function occurs when t=0. At that point, ...
L(0) = d = 7
The next maximum of the oscillation occurs when the argument of the sine function is π/2.
b·t = π/2
b = π/(2t) = π/(2·0.5) = π
At that maximum, the length is 12, so we have ...
L(0.5) = a·sin(0.5π) +7 = 12
a = 5
The function L(t) is ...
L(t) = 5·sin(πt) +7