Find derivative of -sqrt(y)/sqrt(x) and double derivative of sqrt(x)+sqrt(y)=1

Question

anonymous · Answer

derivative of $$-\sqrt{y}/{\sqrt{x}}$$ and double derivative of $$\sqrt{x}+\sqrt{y}=1$$
Than answers to the problems are supposed to be same but it's not happening for me :-(

anonymous · Answer

derivative of  -sqrt(y)/sqrt(x)  is 

[sqrt(x)*(-1/2sqrt(y))*y'-[(-sqrt(y)]*(1/2sqrt(x))] / [sqrt(x)]^2

anonymous · Answer

http://www.wolframalpha.com/input/?i=Differentiate+-sqrt%28y%29%2Fsqrt%28x%29+with+respect+to+x http://www.wolframalpha.com/input/?i=Differentiate+sqrt%28x%29%2Bsqrt%28y%29%3D1+with+respect+to+x