Given f(x)=(x2+1)cos(x)f(x) = (x^2+1)^{\cos(x)}f(x)=(x2+1)cos(x), what is the logarithmic derivative f′(x)/f(x)f'(x)/f(x)f′(x)/f(x)?
-sin(x)ln(x^2+1) + 2xcos(x)/(x^2+1)
cos(x)ln(x^2+1) - 2xsin(x)/(x^2+1)
sin(x)ln(x^2+1) + xcos(x)/(x^2+1)
-cos(x)ln(x^2+1) + sin(x)/(x^2+1)