ds = √(r^2 + r'^2)
r' = 6cos3θ
s = ∫[0,π/3] √(4sin^2(3θ) + 36cos^2(3θ)) dθ
= 2∫[0,π/3] √(1 + 8cos^2(3θ)) dθ
This is an elliptic integral. Good luck.
For the curve r = 2 sin 3(theta):
Find the arc length of one petal
1 answer