If $f(x) = \cot^{-1}\left(\dfrac{3x - x^3}{1 - 3x^2}\right)$ and $g(x) = \cos^{-1}\left(\dfrac{1 - x^2}{1 + x^2}\right)$, then $\lim\limits_{x \to a}\dfrac{f(x) - f(a)}{g(x) - g(a)}$, $\left(0 < a < \dfrac{1}{2}\right)$ is

The coordinates of the points on the curve $4y = x^2$ that are nearest to the point $(0,5)$ are ...

The equation of the tangent to the curve $y = \sqrt{9 - 3x^2}$ at the point where the ordinate and abscissa equal is...

If the line $y = 4x - 5$ is tangent to the curve $y^2 = ax^3 + b$ at the point $(2,3)$, then the value of $7a - 2b$ is...