If y = sqrt(x-1)+sqrt(x+1),prove that sqrt(x^2-1)dy/dx=1y/2

Answer 1

take the derivative

dy/dx= -1/sqrt(x-1) - 1/sqrt(x+1)

= -1( sqrt(x+1) +sqrt(x-1) )/ ( zzzz)

where zzzz= x+1-x+1 (Prove that)which is 2
dy/dx= -y/2