Write a script in MatLab that will model radio-active decay using the formula dx/dt =rx where x is the amount of the radio-active substance at time t and r is the decay rate. Some radio-active substances decay into other radioactive substances which in turn also decay. For example, Strontium 92 (r1 = 0.256/h) decays into Yttrium 92 (r2 = 0.127/h), which in turn decays in to Zirconium. Write down a pair of differential equations for Strontium and Yttrium to describe what is happening. Starting at t=0 with 5 x10^26 atoms of Strontium 92 and none of Yttrium, use the Runge-Kutta method (ode23) to solve the equations up to t=8 in steps of 1/3 h. Plot the results