Hi all,
Here's the problem:
t(dx/dt) + x = t^3
1. dx/dt + x/t = t^2
2. use (1/t) as an integrating factor: e^(int(1/t)dt) = e^(ln t) = t
3. d/dt (xt) = t^3
4. xt = (1/4)t^4 + C
5. x = (1/4)t^3 + C/t
My friend got the answer k(t)(1/t) = t^3/4 + C/t
Did I make a mistake or did he? Or both? Thanks,
Kim