Uploaded September 2022 | Updated September 2026, 1 week ago

---

In this video, I derived a formula for finding the sin of the sum of two angles. In my derivation, I used the cofunction relations and cos(a-b) formula which I proved in my previous videos. You can access those videos below.

Cofunction relations proof: youtu.be/IBFY4faV2s8
cos(a-b) formula proof: youtu.be/w6hNam8nrIY

#trigonometry #maths #math #science #geometry