- High schoolπTrigonometryπ΅
Trig circle: the 4 values to memorize (0Β°, 30Β°, 45Β°, 60Β°, 90Β°)
One raised hand, five fingers, five angles. The mnemonic to remember cos and sin of all usual angles.
- High schoolπTrigonometryπ΅
Trigonometric equations: the unit circle method
cos(x) = a, sin(x) = a, tan(x) = a. All solutions on β using the unit circle.
- Middle schoolπTrigonometryπ
SOH-CAH-TOA: the mnemonic that locks in sin, cos, tan in 30 seconds
Three letters, three rules, zero confusion. The middle-school method everyone remembers for right-triangle trig.
- High schoolπTrigonometryπ΅
cosΒ²(x) + sinΒ²(x) = 1: Pythagoras in disguise
The most-used trig identity of high school is nothing but Pythagoras applied to the unit circle. Proof in 30 seconds.