[tex]\large\sf{\sqrt{\frac{1+sin\theta}{1-sin\theta}}+\sqrt{\frac{1-sin\theta}{1+sin\theta}}}[/tex]
[tex]\\[/tex]
[tex]\large \sf{=\frac{\left(\sqrt{1+sin\theta}\right)^{2}+\left(\sqrt{1-sin\theta}\right)^{2}}{\sqrt{(1-sin\theta)(1+sin\theta)}}}[/tex]
[tex]\\[/tex]
[tex]\large\sf{=\frac{1-sin\theta+1+sin\theta}{\sqrt{1^{2}-sin^{2}\theta}}}[/tex]
[tex]\\[/tex]
[tex]\large \sf{=\frac{2}{\sqrt{cos^{2}\theta}}}[/tex]
[tex]\\[/tex]
[tex]\large\sf{= \frac{2}{cos\theta}}[/tex]
[tex]\\[/tex]
[tex]\large\sf{= 2sec\theta}[/tex]
[tex]\\[/tex]
[tex]\large\sf{=RHS}[/tex]
Therefore,
[tex]\large\sf\red{\sqrt{\frac{1+sin\theta}{1-sin\theta}}+\sqrt{\frac{1-sin\theta}{1+sin\theta}}=2sec\theta}[/tex]