If $\theta+\phi=\frac{\pi}{4}$, then $(1+\tan \theta)(1+\tan \phi)$ is equal to

If $\alpha, \beta, \gamma$ are any three angles,then $\cos \alpha + \cos \beta - \cos \gamma - \cos (\alpha + \beta + \gamma) =$

If two angles $\alpha, \beta$ are such that $0 < \alpha, \beta < \frac{\pi}{4}$,$\sqrt{1+\cos 2 \alpha}=\frac{3}{\sqrt{5}}$ and $\frac{\sqrt{1-\cos 2 \beta}}{\sqrt{1+\cos 2 \beta}}=\frac{1}{7}$,then $(2 \alpha+\beta)=$

If $\alpha+\beta=\gamma$,then what is the value of $\cos^2 \alpha+\cos^2 \beta+\cos^2 \gamma$ equal to?

The value of $\cos 105^\circ + \sin 105^\circ$ is

$\frac{\sin 3\theta + \sin 5\theta + \sin 7\theta + \sin 9\theta}{\cos 3\theta + \cos 5\theta + \cos 7\theta + \cos 9\theta} = $