How do you prove 4 (cos^4a + sin^4a) / (3+cos4a) = (cos^4a-sin^4a) sec2a?

The parabola y = x² - 4 opens: a.) up b.) down c.) right d.) left

Aefg - almn. find the ratio of aefg to almn. a)1: 4 b)1: 2 c)2.1 d)4: 1

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?