Waves and Phases: Understanding 90 and 180 Degrees Out of Phase

[jsmith613]

I believe I was mitaught something in class so would like to double check.

If I had two sin waves, but one was inverted, would the waves be 180^o out of phase. (my teacher said 90 degress out of phase)

If so, how would I draw a graph where the waves are 90 ^o / 270 ^o out of phase

thanks

also, is 360 degrees out of phase the same as 0 degrees out of phase?

if waves are 180 degress out of phase do they cancel each other out?

 

[Naty1]

I'm not going to answer those all those questions...but if you graph or look at a graph of the sine and cosine functions you can figure them out for yourself...then you'll understand.



Note that a simple sine function graph starts from the origin (zero) and increases to a maximum at 90 degrees...the cosine function starts at a maximum and decreases to zero at 90 degress...

How do you make one look like the other? Look at the graphs...use the Y symmetry axis
as your reference...
If you shift a sine wave 90 degress left it looks just like a cosine; shift a cosine wave 90 degrees right it looks just like a sine wave...

Here is one set of graphs: http://en.wikipedia.org/wiki/Cosine_wave

 

[zgozvrm]

To answer your questions:
Yes (your teacher is wrong)
(see Naty1's answer)
Yes
Yes