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.
Veins are blood vessels carrying blood towards the heart, whereas arteries bring blood away from heart. Mostly, arteries contain oxygenated blood, and veins contain carbon dâ¦ioxide-rich and oxygen-poor blood; however, there is one exception.
Arteries are very elastic, are much more resilient than veins and are less likely to be tortuous. Arteries carry blood away from the heart, and veins carry blood back to the heart. This difference in blood pressure means that veins require thinner walls than arteries, according to the Merck Manual, a medical textbook.