How do you differentiate # arctan(x^2+1)#?

2 Answers
Jun 22, 2016

# (2x)/((x^2 + 1)^2 + 1)#

Explanation:

let # y = arctan (x^2 +1)# so #tan y = x^2 + 1#

thus #sec^2 y \ y' = 2x, \qquad y' = (2x)/(sec^2 y)#

using identity #tan^2 + 1 = sec^2# we have

# y' = (2x)/(sec^2 y) = (2x)/((x^2 + 1)^2 + 1)#

Jun 22, 2016

#dy/dx=(2x)/(x^4+2x^2+2).#

Explanation:

Let #y=arctan(x^2+1)#

Then, #dy/dx=d/dx{arctan(x^2+1)} =1/{1+(x^2+1)^2}*d/dx(x^2+1)#................[Chain rule]
#=1/(1+x^4+2x^2+1)*2x=(2x)/(x^4+2x^2+2).#