The principal value of $$\text{sin}^{-1}\space\frac{1}{\sqrt2}$$​ is :

Correct option is C

Given: ​

​$$\text{sin}^{-1}\space\frac{1}{\sqrt2}$$ 

Concept Used: 

​$$\sin 45\degree = \frac1{\sqrt2}$$ 

Solution: 

​$$\text{sin}^{-1}\space\frac{1}{\sqrt2} = \theta \\ \ \\ \frac1{\sqrt2} = \sin \theta \\ \ \\ \sin 45\degree = \sin \theta \\ \ \\ \implies \theta = 45\degree = \frac {\pi}{4}$$​​