The radius of the circle whose arc of length $15 \ cm$ makes an angle of $3/4$ radian at the centre is ..... $cm$.

If $f(x) = \cos^2 x + \sec^2 x$,then

If $\frac{\pi}{2} < \alpha < \pi$ and $\pi < \beta < \frac{3\pi}{2}$,with $\sin \alpha = \frac{15}{17}$ and $\tan \beta = \frac{12}{5}$,then the value of $\sin(\beta - \alpha)$ is: (in $/221$)

If $\tan (A + B) = p$ and $\tan (A - B) = q,$ then the value of $\tan 2A$ in terms of $p$ and $q$ is

If $x = a \cos^3 \theta$ and $y = b \sin^3 \theta$,then:

If ${\sin ^3}x \sin 3x = \sum\limits_{m = 0}^n {{c_m} \cos mx} $ where ${c_0}, {c_1}, {c_2}, \dots, {c_n}$ are constants and ${c_n} \ne 0$,then the value of $n$ is