Root cap is absent in

The cosine of the angle $A$ of the triangle with vertices $A(1, -1, 2)$, $B(6, 11, 2)$, and $C(1, 2, 6)$ is:

For the reaction $2NO_{2(g)} \rightleftharpoons 2NO_{(g)} + O_{2(g)}$,$K_c = 1.8 \times 10^{-6}$ at $185 \ ^oC$. At $185 \ ^oC$,the $K_c$ for the reaction $NO_{(g)} + \frac{1}{2}O_{2(g)} \rightleftharpoons NO_{2(g)}$ is:

Two thin lenses of focal lengths $f_1$ and $f_2$ are in contact and coaxial. The power of the combination is

The length of the tangent drawn to the circle $x^2+y^2-2x+4y-11=0$ from the point $(1,3)$ is:

$\lim _{x \rightarrow 0} \frac{\tan x - \sin x}{x^3}$ is equal to