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.
Veins and arteries are both types of blood vessels but arteries carry blood away from the heart to the rest of the body while veins carry blood to the heart from the rest of the body. All arteries except the pulmonary and umbilical arteries carry oxygenated blood while all veins carry deoxygenated blood. The arteries are basis of the circulatory system and their main function is to deliver oxygen and nutrients through blood to all the cells in the body.