From e73b7959cc34a8cf2562dde234b0b750c6f4cd5f Mon Sep 17 00:00:00 2001 From: craisin Date: Fri, 30 Jan 2026 22:12:45 -0800 Subject: [PATCH] vault backup: 2026-01-30 22:12:45 --- Petals in a Rose Curve.md | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Petals in a Rose Curve.md diff --git a/Petals in a Rose Curve.md b/Petals in a Rose Curve.md new file mode 100644 index 0000000..592ca34 --- /dev/null +++ b/Petals in a Rose Curve.md @@ -0,0 +1,32 @@ +#Math #Trig #Algebra +# Question +Show there are $n$ petals in a rose curve with odd $n$ and $2n$ petals in a rose curve with even $n$. +# Solution +WLOG the rose curve has the form $r = \cos n\theta$. +Then there are 2 cases to get a maximum point on a petal: either $\cos n\theta = 1$ or $\cos( n(\theta + \pi)) = -1$ +## Case 1 +$$ +\cos n\theta = 1 +$$ +For all integers $i$: +$$ +n\theta = 2i\pi +$$ +$$ +\theta = \frac {2i\pi} n +$$ +## Case 2 +$$\cos( n(\theta + \pi)) = -1$$ +For any arbitrary integer $i$: +$$n(\theta + \pi) = 2i\pi + 1$$ +$$\theta = \frac {(2i + 1)\pi - n\pi} n$$ +For $\theta \in [0, 2\pi)$ both sequences create +## Even Case +Factor out $\frac \pi n$ from both sides. Case 1 has $\frac \pi n$ multiplied by an even factor, while case 2 has $\frac \pi n$ multiplied by an odd factor. Therefore the sequences are unique, creating $2n$ unique petals. +## Odd Case +Take case 2: +$$\theta = \frac {(2i + 1)\pi - n\pi} n$$ +$$\theta = \frac {2i\pi + (1 - n)\pi} n$$ +Since $n$ is odd, $1 - n$ is even, and therefore the numerator is an even factor of $\pi$. +$$\theta = \frac {2i\pi} n$$ +Therefore case 2 produces the same $\theta$ as case 1, resulting in $n$ petals. \ No newline at end of file