Proof of the Sum and Difference Trig Identities

 

Here's a way to generate the sum and difference identities for sine and cosine!

Fun fact: I sped up the video so my voice sounds higher than it is in real life. 😀

You may be interested in my Sum and Difference Identities Circuit.

Disclosure: Some of the links below are affiliate links. This means that, at zero cost to you, I will earn an affiliate commission if you click through the link and finalize a purchase.

I recorded this with my iPad using the GoodNotes app and an Apple Pencil. I used the screen recorder built into the iPad. For the microphone, I used my wireless earbuds then I did a bit of editing with an app called InShot.