C
Because I had this question
Answer:
Explanation:
19.
P = 2(x - 3 + 7x + 1)
= 2(8x - 2)
= 16x - 4
20.
P = 3y + 5 + y - 4 + 6y
= 10y + 1
Answer:
is an even function.
Step-by-step explanation:
Recall when it means when a function is even or odd. An even function has the following property:

And an odd function has the following property:

So, let's test some values for cos(x).
Let's use π/3:

From the unit circle, was can see that this is 1/2 (refer to the x-coordinate).
Now, let's find -π/3. This is the same as 5π/3. Thus:

And again from the unit circle, we can see that this is 1/2.
Therefore, despite the negative, the function outputs the same value.
Cosine is an even function.
Notes:
Cosine is an even function and sine is an odd function. It's helpful to remember these as they can help you solve some trig problems!