InterviewSolution
Saved Bookmarks
| 1. |
Lety(x) be the solution of the differential equation `(xlogx)(dy)/(dx)+y=2xlogx ,(xgeq1)dot`Then y(e) is equal to :(1)e (2) 0 (3) 2 (4) 2eA. (a) eB. (b) 0C. (c) 2D. (d) 2e |
|
Answer» Correct Answer - (c) Given differential equation is `(x log x)dy/dx+y=2xlogx` `rArr dy/dx+y/(xlogx)=2` This is a linear differential equation. `therefore IF= e^(int1/(x logx)dx)=e^(log(logx))=log x` Now, the solution of given differential equation is given by `y cdot log x = int log x cdot 2dx` `rArr y cdot log x = 2 int log x dx` `rArr y cdot log x = 2 [x log x-x]+c` At `x = 1 rArr c = 2` `rArr y cdot log x = 2 [x log x-x]+2` At `x=e, y=2(e-e)+2` `rArr y = 2` |
|