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## Homework Statement

Find the arc length of the curve r=4/θ, for ∏/2 ≤ θ ≤ ∏

## Homework Equations

L= ∫ ds = ∫ √(r^2 + (dr/dθ)^2) dθ

## The Attempt at a Solution

After some calculations, and letting θ = tanx, I now have to find ∫ ((secx)^3/(tanx)^2). I am not sure how to do this, but i have found online that ∫ (secx)^3 = (1/2)sec(x)tan(x)+(1/2)ln|sec(x)+tan(x)|. Using integration by parts and letting u = 1/(tan(x))^2= (cot(x))^2 and du/dx = -2cot(x).(cosec(x))^2 is looking very tedious. How do I solve this problem correctly?