Question

Choose the graph of y = 2 cos x.

Answer 1

thats it

Answer 2

the graph of cos x goes through 0 , pi and 2pi on x-axis

multiply this by 2 will stretch the graph parallel to y-axis by a factor of 2

- this should help

Answer 3

the second graph correct?

Answer 4

nope... the amplitude must be 2

Answer 5

Even if you don't know the shape of the cosine (which you should learn),
you could do this:

what is cos(0º) ? (another fact you should learn, it is 1)
what is 2*cos(0)? 2*1= 2
then look at each graph and see if at x=0 you get that value (2)

Answer 6

3rd one right?

Answer 7

the 4th graph is correct due to the fact that cosine starts above the x axis not like sin thats starts right on the x axis. also the 4th graph starts at 2

Answer 8

the 3rd graph has y= 3 at x=0

but you (should!) know 2*cos(0)= 2