The derivative of inverse trigonometric identities follow<span> a set of rules. </span> <span>For </span>arc cos<span> x, the </span>dy/dx is equal to -1/ square root of (1 - x2). <span>In this case, we still have 1/2 x inside the angle quantity so we multiply the </span>dy/dx above with 1/2. Hence, y' = is -1<span>/ 2 square root of (1 - x2); x = 1, y' is infinity. this means the line is horizontal. The answer hence is y = 1.</span>
