sin^-1(2sin theta) +sin^-1(cos2 theta) =

Question : $\sin ^4 \theta+\cos ^4 \theta$ in terms of $\sin \theta$ can be written as:

Option 1: $2 \sin ^4 \theta+2 \sin ^2 \theta-1$

Option 2: $2 \sin ^4 \theta-2 \sin ^2 \theta$

Option 3: $2 \sin ^4 \theta-2 \sin ^2 \theta-1$

Option 4: $2 \sin ^4 \theta-2 \sin ^2 \theta+1$

Question : What is the value of $\frac{\sin \theta+\cos \theta}{\sin \theta-\cos \theta}+\frac{\sin \theta-\cos \theta}{\sin \theta+\cos \theta}$?

Option 1: $\frac{1}{\left(\sin ^2 \theta-\cos ^2 \theta\right)}$

Option 2: $2\left(\sin ^2 \theta-\cos ^2 \theta\right)$

Option 3: $\frac{2}{\left(\sin ^2 \theta-\cos ^2 \theta\right)}$

Option 4: $\sin ^2 \theta-\cos ^2 \theta$

Question : $\sqrt{\frac{1+\sin\theta}{1-\sin\theta}}+\sqrt{\frac{1-\sin\theta}{1+\sin\theta}}$ is equal to:

Option 1: $2\cos\theta$

Option 2: $2\sin\theta$

Option 3: $2\cot\theta$

Option 4: $2\sec\theta$