The brightness of some stars can fluctuate over time. Assume that brightness of the certain star can be modeled by following: B(t) = 7.8 + 10.8sin((2pi/63)t) In the equation, B(t) represents magnitude of brightness, and t is time (in days). Assume we start at t = 0 days. During first 63 days, when will star's magnitude of brightness be 13?