I keep getting “Pythagorean identity” questions wrong in Trigonometry. What's the trap?
misremembering it as sinθ + cosθ = 1.
The usual trap: misremembering it as sinθ + cosθ = 1. How to avoid it: it's the SQUARES that add to 1, from the unit circle. Go back to the definition — for any angle, sin²θ + cos²θ = 1.
Key point
Pythagorean identity
Common mistake
misremembering it as sinθ + cosθ = 1.
Memory tip
it's the SQUARES that add to 1, from the unit circle.
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