Constant FRAC_PI_2 

pub const FRAC_PI_2: f128 = 1.57079632679489661923132169163975144209858469968755291048747_f128 /* 1.5707963267948966192313216916397514f128 */;

🔬This is a nightly-only experimental API. (f128 #116909)

π/2