Sign Changes And Co Function Identities On The Circle
An animation using the unit circle to show how trigonometric ratios transform under angle shifts like (π/2 ± θ), (π ± θ), and (2π − θ). It highlights when sine turns into cosine (co-function swap) and when the sign flips based on the quadrant of the resulting angle, using the ASTC rule. Useful for students memorizing trigonometric identities and teachers explaining the geometric reasoning behind sign and ratio changes instead of rote memorization.
Narrated · 16:9 · Preview before teaching · automatic layout checks do not establish subject accuracy
The prompt that made it
Show how the ratios changes its sign or son tp cos, cos to sin on the basis of cordant and angle like 2pi-theta, pi/2-/+theta etc
Make the next one in this series
- Show why tan(π/2 − θ) equals cot θ using a right triangle rotation
- Animate the ASTC rule with a rotating radius across all four quadrants
- Derive sin(A ± B) formulas visually using two overlapping triangles
