# sketch sin graph

• February 20th 2011, 11:07 AM
andyboy179
sketch sin graph
hi, i nned to put these into a sin graph:
Y=sinx
Y=sin(x+90)
Y=3sinx

i can to the first and third ones but not the second, would it look like this:

Attachment 20879

if this is incorrect can someone please tell me how to improve.

thanks!
• February 20th 2011, 12:19 PM
pickslides
You have the general idea with the intercepts and turning points correct for one cycle.

I know the software used tricky to master but you must understand the function is a smooth curve. I would use technology to see this.
• February 20th 2011, 12:27 PM
e^(i*pi)
Apart from the fact it should be a curve the graph (intercepts, maxima etc) are fine.

You may notice that the graph is the same as $y = \cos(x)$
• February 20th 2011, 12:30 PM
andyboy179
I know it has to be a curve but I haven't got the software for this so I have to use 'paint'. So what I have posted is correct apart from when I actually do it on paper I draw curves?
• February 20th 2011, 12:34 PM
e^(i*pi)
Yes - like on this pic (yes I know it says cos(x) but it's the same graph)

http://content.tutorvista.com/maths/...ges/img670.gif