List of top Mathematics Questions on sections of a cone

cos \( A \cos 2A \) is equal to:

Given that: \[ \frac{1}{\tan A - \tan B} = \]

If the foci of the ellipse $ \frac {x^{2}} {{16}}$+$ \frac {y^{2} }{{b}^2} $=1 and hyperbola $\frac {x^{2}} {144} - \frac {y^{2}}{81}=\frac {1}{25}$ coincide then the value of $b^2$ is