Question

graph y=2cosx

Answer 1

@eliassaab my graph looks like this one but is shifted, is that a problem?

Answer 2

No, it depends which interval you are using for graphing. Notice that cos(2 x) is periodic of period \(\pi\)

Answer 3

1 moment, i am emailing myself the picture of my work then ill put here

Answer 4

Be careful cos(0) =1

Answer 5

and not zero

Answer 6

the first coordinate?

Answer 7

Your graph is not right as pictured. It does not go through the origin.

Answer 8

ok, what did i do wrong? my wave is the same, but shifted to the right

Answer 9

http://www.wolframalpha.com/input/?i=plot+2+cos%28+x%29
Here is the graph. My first graph was for cos(2x)

Answer 10

did i set up my coordinate table wrong?

Answer 11

that isnt the problem though, the problem is
y=2cosx

Answer 12

Your confusing sin and cos. cos(0) =1 and not zero

Answer 13

That is why I gave you the second link

Answer 14

i see the graph, but i dont see an explamation of how to get the graph

Answer 15

what did i do wrong in setting up my table of coordinates?

Answer 16

hey man, i figured it out. cosx=cos0=1 because trig functions of quadrantal angles

Answer 17

y=2cosx
1.) Plug value in X, and solve to get Y
this gets you your xy values

2.) x=0,pi/2, pi, 3pi/2 2pi this is what we plug in to get y value

3.) use the unit circle values, cos is x coordinate, sin is y coordinate(cos,sin)

4.) y=2cos(0),
2*1=2, so y=2,

y=2cos(-1) at pi
2(-1)=-2, so y=-2

y=2cos (0), at pi/2
2*1=2, so y=2

y=2cos (0), at 3pi/2
2(1)=2, so y=2

y=2cos(1), at 2pi
2(1)=2, so y=2

5.) so x values= 0,pi,pi/2,2pi,3pi/2
y values= 2, -2, 2, 2, 2
Understand?

Answer 18

yes sir, i understand. that sending me to a website crap doesnt help. heck, i already went to websites before posting my question, it didnt help. posting websites doesnt help. again thank you

Answer 19

I agree, sorry I am a slow typer, Im glad you understand, feel free to ask me any questions!

Answer 20

no problem, ill be patient for a thorough explanation anyday