What is asin (Wx + φ) + B = (ymax + yman) / 2

What is asin (Wx + φ) + B = (ymax + yman) / 2

y=Asin(wx+φ)+B
So: ymax = a + B, yman = - A + B
So: ymax + yman = 2B
So: B = (ymax + yman) / 2