Plz also teel how it is used in C++

asin() in <cmath>
Try here for a description.

asin() in <cmath>
Try here for a description.

Yeah that's truly right !

You just use it like the sin function ...

>>You just use it like the sin function ...
Caution!! the Domain of arcsine function is from [-1.1]. I suppose the OP would be aware of this since he is dealing with it.
Also, return value is the principal value: -pi/2 to +pi/2

PS: I know all this must be in the reference of the asin given by Nucleon but I was cautioning since it was pointed "use as you use sine".

>>> You can use it like the sin function

I said that because the function prototypes of the sin and asin function are the same ...