Marco's equation is correct. Cosine is an even function, which means that for every x, f(-x) = f(x). In other words, you get the same answer for a negative value that you would for its corresponding positive value.
Answer:
[-9,∞)
Step-by-step explanation:
If<span> it is perfectly clear which angle is being named, an angle may be referred to by its ... Supplementary Angles are </span>2 angles<span> the </span>sum<span> of whose </span>measures<span> is </span>180<span>°. ... THEOREM: </span>If<span> two congruent angles form a </span>linear pair<span>, </span>they<span> are right angles.</span>
