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.
Arteries, on the other hand, are classified as systemic (part of the cardiovascular system), pulmonary (carry blood to the lungs), aorta and arterioles. Arteries carry bright red blood as it is oxygenated while veins have the dark red blood. Arteries progressively divide into smaller tubes unlike veins.
Arteries carry blood away from the heart, while veins carry blood towards the heart. Capillaries carry blood from arteries to veins. Arteries generally carry oxygenated blood from the heart to the tissues and organs during the systolic heartbeat cycle. They are under high pressure. (the only exception is the pulmonary arteries which carries deoxygenated blood from the heart to the lungs).