Question

describe the domain and range of f(x) = 2cos(x)

Answer 1

@tkhunny

Answer 2

Cosine, like sine, oscillates between 1 and -1.

What does the 2 do?

Answer 3

i don't know :(

Answer 4

If you are 1 and we multiply you by 2, what are you now?

Answer 5

2

Answer 6

This is all you need for a solution.

Answer 7

so the domain is all real numbers and the range is just 2?

Answer 8

No, what happened to -1?

BTW, we talking about the Range. The Domain is All Real Numbers.

Answer 9

so (-1, 2) ?

Answer 10

Why didn't you multiply it by 2?

Answer 11

If it's just the sine or cosine, we have [-1,1]
Multiply it by 2 and we have [-2,2]

If it's just the sine or cosine, we have [-1,1]
Subtract 5 and we have [-6,-4]

You really should look at more of these graphs.

Answer 12

so you're saying the range is (-2, 2) ?

Answer 13

Is there a difference between parentheses and square brackets?

Answer 14

no?

Answer 15

There should be. (-2,2) means not quite -2 or 2, but everything between them. [-2,2] means everything between AND includes the two endpoints.

Answer 16

okay.

Answer 17

Well, there you have it.