import math


def tmit2tmis(tmit: float) -> float:
    """Convert from transmittance to transmissivity."""
    tmis = round((math.sqrt(0.8402528435 + 0.0072522239 * tmit**2)
                  - 0.9166530661) / 0.0036261119 / tmit, 3)
    return max(0, min(tmis, 1))