Here is the answer for this question.
Answer:
always
Answer:

Step-by-step explanation:
We know by definition that the cosine is an even function, therefore

We also know that the sin is an odd function, therefore

By definition:

Then:


Using these trigonometric properties we can simplify the expression

Answer:
That does to make sense...
Maybe extend the question
X 1 = 1 ; X 2 = -2
Step-by-step explanation:
We clear the whole numbers, equal to (zero) and use the calculation formula of the quadratic function, according the image:
Answer: which question?????????????????? all of them????
Step-by-step explanation: