Here ,
#sqrt(xy)=x-y/(x-1)#
Diff. each term w.r.t. #x#, (using product,quotient and chain rules)
#1/(2sqrt(xy))*d/(dx)(xy)=1-((x-1)y_1-y(1))/(x-1)^2#
#=>1/(2sqrt(xy))[xy_1+y*1]=1-y_1/(x-1)+y/(x-1)^2#
#=>(xy_1)/(2sqrt(xy))+y/(2sqrt(xy))=1-y_1/(x-1)+y/(x-1)^2#
#=>(xy_1)/(2sqrt(xy))+y_1/(x-1)=1+y/(x-1)^2-y/(2sqrt(xy))#
#y_1{x/(2sqrt(xy))+1/(x-1)}=(2sqrt(xy)(x-1)^2+2ysqrt(xy)-y(x-
1)^2)/(2sqrt(xy)(x-1)^2)#
#y_1{(x^2-x+2sqrt(xy))/(2sqrt(xy)(x-1))}#=#(2sqrt(xy)(x-
1)^2+2ysqrt(xy)-y(x-1)^2)/(2sqrt(xy)(x-1)^2)#
#y_1(x^2-x+2sqrt(xy))=(2sqrt(xy)(x-1)^2+2ysqrt(xy)-y(x-1)^2)/((x-1))#
#:.y_1=(2sqrt(xy)(x-1)^2+2ysqrt(xy)-y(x-1)^2)/((x^2-x+2sqrt(xy))(x-1))#
Where, #y_1=(dy)/(dx)#