# Trigonometry Identities: cos(2π + x), sin(2π + x), cos(π/2 -x), sin(π/2 -x)

(Edited)

In this video I show some very useful trigonometric identities which basically involve shifting the sine or cosine functions by either 2π or 360 degrees and π/2 or 90 degrees. Make sure you understand these and keep them in mind because I will use these many times in later videos.

### View Video Notes Below!

View these notes as an article: https://peakd.com/@mes
Subscribe via email: http://mes.fm/subscribe
Donate! :) https://mes.fm/donate
Subscribe to MES Truth: https://mes.fm/truth

Reuse of my videos:

• Feel free to make use of / re-upload / monetize my videos as long as you provide a link to the original video.

Fight back against censorship:

• Bookmark sites/channels/accounts and check periodically
• Remember to always archive website pages in case they get deleted/changed.

Recommended Books:

Join my forums!

Follow along my epic video series:

NOTE #1: If you don't have time to watch this whole video:

Browser extension recommendations:

# Trigonometry Identities

## cos(2π + ϴ) = cos(ϴ) and sin(2π + ϴ) = sin(ϴ)

Adding 2π is the same as adding 360°; which means we can just rotate the angle by a full revolution until it gets back to the same line. The ratios stay the same so the identity becomes itself!

## cos(π/2 - ϴ) = sin(ϴ) and sin(π/2 - ϴ) = cos(ϴ)

Subtracting an angle from π/2 is the same as subtracting it from 90°; which means the resulting ratios get flipped as per the image below.

0
0
0.000

Thanks for your contribution to the STEMsocial community. Feel free to join us on discord to get to know the rest of us!

Please consider delegating to the @stemsocial account (85% of the curation rewards are returned).

You may also include @stemsocial as a beneficiary of the rewards of this post to get a stronger support.

0
0
0.000