Posted by colin on September 23, 2002 at 11:17:22:
I'm also at an impasse on this prob:
yy'' + (y')^2 = 0
let v = y'
dv/dt = y'' = (dv/dy)(dy/dt) = v(dv/dy)
yv(dv/dy) + v^2 = 0
dv/dy = -v/y
dv/v = - dy/y
ln(v) = -ln(y) + c1
v = -y + c1
somehow the book answer is v = c1/y at this point.
I don't see how they got that...
Post a Followup