The arctangent is the inverse tangent function. Since. tan Ï/4 = tan 45Âº = 1. The arctangent of 1 is equal to the inverse tangent function of 1, which is equal to Ï/4 radians or 45 degrees: arctan 1 = tan-1 1 = Ï/4 rad = 45Âº. 1  Arctan.  Arctan calculator.
1 The difference is that an artery brings blood to the body and a vein takes blood to the lungs.  Arteries and Veins are part of the circulatory system, where arteries carry the blood from the heart to the organs, and the veins carry it from the organs to the heart again.
Arteries carry blood away from the heart. Veins carry blood toward the heart. Whether or not that blood is oxygenated is not exclusively related to whether or not it's an artery or a vein. For example, the pulmonary artery carries deoxygenated blood while the carotid artery carries oxygenated blood.