Answer to Question #50897 in Differential Equations for Nayan Jyoti Das

Question

4. a) A wet porus substance in the open air loses its moisture at a rate proportional to the moisture
content. If a sheet hung in the wind loses half its moisture during the first hour, then find the
time when it has lost 95% moisture provided the weather conditions remain the same.

b) If the interest is compounded continuously, the amount of money invested increases at a rate
proportional to its size. Let Rs. 10,000 be invested at 10% compounded continuously. Then in
how many years will the original investment double itself ?

c) Solve: dy/dx + (x/1-x^2) y = xy, y(0)=1.