Differential equation problem

1. Mar 20, 2014

lap

The question ask to determine whether y = φ(x) = sqrt ( x - 1 ) is a solution of the differential equation 2yy' = 1.

Last edited: Mar 20, 2014
2. Mar 20, 2014

HallsofIvy

Staff Emeritus
As far as "determine whether y = φ(x) = sqrt ( x - 1 ) is a solution of the differential equation 2yy' = 1" is concerned, there is no reason to "rewrite the equation". If y= sqrt(x- 1)= (x-1)^(1/2) then y'= (1/2)(x- 1)^(-1/2) so that 2yy'= 2(x- 1)^(1/2)[(1/2)(x- 1)^(-1/2)= what?

As for the rest, I don't see how that has anything to do with the problem. Are you sure you haven't looked up the solution to the wrong question?

3. Mar 20, 2014

Mugged

Your wording is a bit confusing but if you're trying to determine if y(x) is a solution to your differential equation, all you have to do in plug y(x) into the equation and check if it holds.

4. Mar 21, 2014

HallsofIvy

Staff Emeritus
lap has edited his question and changed it completely. My first response was to a different question.