Every box from the classic Dawkins trig cheat sheet — definitions, the unit circle, identities, angle-sum formulas, inverse functions, and the Laws of Sines & Cosines — rebuilt so you can drag an angle and watch both sides of a formula compute in real time.
Two equivalent pictures of the same six ratios: a right triangle (for 0°<θ<90°) and the unit circle (for any angle at all). Drag either slider.
Pick a function and stretch it with ω. The dashed vertical lines mark where it's undefined (outside its domain); the shaded band shows its range; the amber ticks mark one computed period T.
All the standard angles at once. Pick one to see its exact coordinates and exact sin/cos/tan values — for any point (x,y) on the unit circle, cos(θ)=x and sin(θ)=y.
Set θ and every identity below computes both sides live — a match confirms the identity holds for that angle (undefined cases are shown as "—" rather than a false mismatch).
| Identity | LHS | RHS | Match |
|---|
Set α and β and watch double-angle, sum/difference, product-to-sum and sum-to-product formulas all check out numerically at once.
| Formula | LHS | RHS | Match |
|---|
Enter x. Each inverse function only accepts x in its domain — out-of-range boxes are grayed out.
| Function | Domain | Range |
|---|---|---|
| y = sin⁻¹(x) | −1 ≤ x ≤ 1 | −π/2 ≤ y ≤ π/2 |
| y = cos⁻¹(x) | −1 ≤ x ≤ 1 | 0 ≤ y ≤ π |
| y = tan⁻¹(x) | −∞ < x < ∞ | −π/2 < y < π/2 |
Give two sides and the angle between them (γ, opposite side c); the rest is computed and checked with the Law of Sines and Mollweide's formula.