Q.

If x = x(t) is the solution of the differential equation (t+1)dx=(2x+(t+1)4)dt, x(0) = 2, then x(1) equals __________.           [2024]


Ans.

(14)

We have, (t+1)dx=(2x+(t+1)4)dt

 dxdt=2xt+1+(t+1)3; P=2t+1, Q=(t+1)3

So, I.F. =ePdt=e2t+1dt=e2 log (t+1)=(t+1)2

The Solution of given differential equation is given by x(I.F.)=Q·(I.F.)dt+C

 x(t+1)2=(t+1)3(t+1)2dt+C

 x(t+1)2=(t+1)dt+C  x=(t+1)2[t22+t+C]

Putting x(0) = 2, we get

2=(1)2(0+0+C)  C=2

   x=(t+1)2(t22+t+2)

At t=1, x = (2)2(12+1+2)=4(72)=14.