Finding arc length of a polar curve with tangent lines

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suporia
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Not homework, just trying to learn how to solve this problem for an exam.

Homework Statement



https://dl.dropbox.com/u/23889576/Screenshots/10.png

Homework Equations



[itex]\int_{a}^{b} \sqrt { (\frac{dr}{dθ})^2 + r^2 }\, dθ[/itex]

The Attempt at a Solution



Had much difficulty, could not even derive the original derivative function for this problem.
 
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welcome to pf!

hi suporia! welcome to pf! :wink:

the figure is symmetric, so when one bug is at (r,θ), the next is at (r,θ+π/2) …

does that help? :smile: