Let $f(x) = {\cos ^{ - 1}}\left( {\frac{{2x}}{{1 + {x^2}}}} \right) + {\sin ^{ - 1}}\left( {\frac{{1 - {x^2}}}{{1 + {x^2}}}} \right)$ then the value of $f(1) + f(2)$, is -
$-\pi$
$0$
$\pi$
$2\pi$
Let $c, k \in R$. If $f(x)=(c+1) x^{2}+\left(1-c^{2}\right) x+2 k$ and $f(x+y)=f(x)+f(y)-x y$, for all $x, y \in R$, then the value of $|2( f (1)+ f (2)+ f (3)+\ldots \ldots+ f (20)) \mid$ is equal to
Domain of the function $f(x) = {\sin ^{ - 1}}(1 + 3x + 2{x^2})$ is
If $P(S)$ denotes the set of all subsets of a given set $S, $ then the number of one-to-one functions from the set $S = \{ 1, 2, 3\}$ to the set $P(S)$ is
The graph of the function $y = f(x)$ is symmetrical about the line $x = 2$, then
The domain of the function $f(x) = {\sin ^{ - 1}}[{\log _2}(x/2)]$ is