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`


Discussion

No Comment Found

Related InterviewSolutions