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. Veins carry blood back to the heart. They carry deoxygenated blood away from the body. The blood returning from the body is at a much lower pressure than that being pumped from the heart. Therefore veins do not have to be as strong as arteries. Veins are wider than arteries and have much thinner walls.Look at the image below to see the main difference between arteries and veins.he blood returning from the body is at a much lower pressure than that being pumped from the heart. Therefore veins do not have to be as strong as arteries. Veins are wider than arteries and have much thinner walls. Look at the image below to see the main difference between arteries and veins.