The lowest common denominator<span>, or </span>LCD<span>, denotes the smallest number divisible by the denominators of every fraction in a set, whereas a </span>least common multiple, orLCM<span>, is the smallest multiple that two numbers have in common as products. Finding the </span>LCD<span> and </span>LCM<span>requires knowing prime factors of a number.</span>
= (cos2x+1)(cos2x+1)/4 