peek at solution solve puzzle
quality: difficulty: solvability: moderate lookahead
Puzzle Description:
A (relatively) simple way to visualize the basic trigonometric subtraction/addition identities. In this case there is a 9-12-15 triangle and a 12-16-20 triangle. They combine to make, roughly, a 7-24-25 triangle. As much as I'd like to use more complex numbers, it would make the image too big. Also I kept getting alternate solutions until I made the lines a bit thick. Another way I remember figuring the formulas was to, say, set x=y or x=0 and then I could figure match up which sin/cos products went with which. I'm not sure how I learned it in high school. My teacher was very good, but I had to memorize the formulas. But I was pleased to find a diagram like this when I googled years later.
#1: Web Paint-By-Number Robot (webpbn) on Apr 10, 2022
Found to be solvable with moderate lookahead by blurglecruncheon.#2: Andrew Schultz (blurglecruncheon) on Apr 10, 2022 [HINT]
Comment Suppressed:Click below to view hints#3: Christine Freer (cfreer) on Apr 10, 2022
All this maths hurts my head!#4: Kristen Vognild (kristen) on Apr 11, 2022 [SPOILER]
When I was on the math team, we would draw a circle with 30-45-60-90-120-135-150-180-210-225-240-270-285-300-315-330 and 360 degrees marked (in 12ths and in 4ths), and write in the sin and cos of each degree measure. We would draw these daily, and see how fast we could make them, so that they'd be burned into our memories.#5: Kathy Roth (clyde) on Apr 26, 2022
Wow.
Show: Hints
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