Mark the correct alternative in the following:

The function f(x) = cos^{–1} x + x increases in the interval.

Formula:- The necessary and sufficient condition for differentiable function defined on (a,b) to be strictly increasing on (a,b) is that f’(x)>0 for all x(a,b)

Given:-

f(x) = cos^{–1} x + x

Now

f^{’}(x)>0

xR

x(–∞, ∞)

1