$Ni$ anode is used in the electrolytic extraction of

The transformed equation of $3x^2 - 4xy = r^2$ when the coordinate axes are rotated about the origin through an angle of $\operatorname{Tan}^{-1}(2)$ in the positive direction is:

If the lines $2x + 3y + 12 = 0$ and $x - y + k = 0$ are conjugate with respect to the parabola $y^2 = 8x$,then $k$ is equal to

$\int \frac{dx}{\sqrt{x-x^2}}$ is equal to

Which of the following is a tricarboxylic acid?

The eccentricity of the ellipse $9x^2 + 5y^2 - 18x - 20y - 16 = 0$ is: