How to find the difference of 1st minima point of 2 shifted cosine/sine wave in matlab?

I would like to ask if there is a way to get the 1st minima point of 2 cosine wave (one shifted to the right) and evaluate the difference in the x-axis (which is also the time-axis)?

[William]

Not sure is it my questions are unclear, but what I would like to ask is how to find the phase shift of the 2 similar graphs example as above...

Hope someone will be able to help me soon.. :)

Answer 1

[ToLos Mil]

Considering that you have 2 vectors cos1 and cos2 (of the same frequency) you can calculate their phase difference in rad using the formula:

acos(dot(cos1,cos2)/(norm(cos1)*norm(cos2)))

[William]

Thanks a lot apostolos! However, I have currently more troubled and sticky question in another thread... the topic is "how to determine each local min point?" I have a sample coding which i have generated in a simplified version but this time, the angle is a variation of x... do take a look and hope to hear from anyone for urgent solutions... :)

once again, thanks!