Question #d4611

1 Answer
Oct 8, 2017

#dy/dx=-2/(x^2+1)# or #(-2x^(-1))/[x+x^(-1)]#

Explanation:

#y=cos^(-1) [(x-x^(-1))/(x+x^(-1))]#

=#cos^(-1) [(x^2-1)/(x^2+1)]#

Take cosine both sides,

#cosy=(x^2-1)/(x^2+1)#

Take differentiation both sides,

#-siny*dy=[2x*(x^2+1)-2x*(x^2-1)]*dx/(x^2+1)^2#

#-sqrt[1-(cosy)^2]*dy=(4x*dx)/(x^2+1)^2#

#-sqrt(1-[(x^2-1)/(x^2+1)]^2)*dy=(4x*dx)/(x^2+1)^2#

#-sqrt[(4x^2)/(x^2+1)^2]*dy=(4x*dx)/(x^2+1)^2#

#-(2x*dy)/(x^2+1)=(4x*dx)/(x^2+1)^2#

#dy/dx=(4x*dx)/(x^2+1)^2*-(x^2+1)/(2x)#

#dy/dx=-2/(x^2+1)# or #(-2x^(-1))/[x+x^(-1)]#