What is the derivative of #arctan(cosθ)#?
1 Answer
Feb 14, 2016
# -sintheta/(1 +cos^2theta)#
Explanation:
using the following facts :
#d/dx(tan^-1x) = 1/(1 + x^2)# differentiating using the
#color(blue)(" chain rule ")#
#d/dx[f(g(x))] = f'g(x).g'(x)#
#d/dx[tan^-1(costheta)] = 1/(1 + cos^2theta) d/dx(costheta)#
#= -sintheta/(1+ cos^2theta)#
