At high temperatures, nitrogen dioxide, NO₂, decomposes into NO and O₂. If y(t) is the concentration of NO₂ (in moles per liter), then at 600°K, y(t) changes according to the reaction law dy/dt = -0.05y² for time t in seconds.
A. Express y in terms of t and the initial concentration y_0.
B. Assuming that the concentration of NO₂ is twice as high at t = 20 seconds as it is at 100 seconds, find the exact initial concentration of the NO₂.
