Particular Integrals?

Im trying to solve this y' = radq(y/x) whith [y(1) = 4] i have found the integration ... and its [ y = x (c2/4)] or [y = (sqrt(x) (c/2))] but the problem is with the C value ... when i try to find it .... it gives me a different vlue than the value which is on the book answers .. the book answer is [y = (sqrt(x) 1)2] i have already done many others particular Integrals .. in which the C was not touched .. i mean that C was just a simple C ... not a C2 ... and there the answers were right ...but not here .. Can some one help me im a newbie ... sorry for my english ... edit : Can any one tell me how to find the value of ""t"" in this equation : ln(sqrt(1/2t)) = ( ln|x| ) c ---- the same problem ... i dont understand if when i raise the ln equation to "e" .. do i have to raise the C too .. or not .. do i have to do like : eln(sqrt(1/2t)) = eln|x| ec or eln(sqrt(1/2t)) = eln|x| c ????? how do i have to procede to get the "t&