The unit circle has radius = 1.
Any point on it is (cos θ, sin θ).
Drag the dot on the circle, use the slider, or press Play! 🌀
45°
📈 Sine Symmetry Identities
Your neighbor showed: sin(x) = sin(180° − x) ← mirror across 90° sin(x) = −sin(180° + x) ← flip & mirror
Drag the dot on the circle or scrub along the wave — watch the identities hold! 🪞
50°
➕ The Magic Sum Formula
Your neighbor wrote: 1 + 2 + 3 + ... + n
The shortcut is: n × (n+1) / 2
Let's see it block by block! 🧱