$\frac{1}{\cos ^{2} \theta}-1 = \ldots$

$\tan ^{2} \theta - \sec ^{2} \theta = \ldots \ldots \ldots$

If $2 \sin^{2} \theta - \cos^{2} \theta = 2$,then find the value of $\theta$. (in $^{\circ}$)

$\sin ^{2} 1^{\circ} + \sin ^{2} 3^{\circ} + \sin ^{2} 87^{\circ} + \sin ^{2} 89^{\circ} = \ldots$

If $\sin ^{2}(3 x+30^{\circ})+\cos ^{2}(2 x+45^{\circ})=1$,then $x = \dots$ (in $^{\circ}$)

The value of the expression $\left[\operatorname{cosec}(75^{\circ}+\theta)-\sec(15^{\circ}-\theta)-\tan(55^{\circ}+\theta)+\cot(35^{\circ}-\theta)\right]$ is