How do you find the derivative of #ln(x+sqrt((x^2)-1))#?

1 Answer
Jul 28, 2016

#1/sqrt(x^2-1)#

Explanation:

#d/dx ln(x+sqrt(x^2-1)) = 1/[x+sqrt(x^2-1)] * d/dx(x+sqrt(x^2-1))# (Standard differential and Chain rule)

#= 1/[x+sqrt(x^2-1)] * (1 + 1/2(x^2-1)^(-1/2) * d/dx(x^2-1))#
(Power rule and Chain rule)

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

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

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

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

#= 1/(sqrt(x^2-1))#