What is the arclength of the polar curve f(theta) = 2thetasin(5theta)-cottheta f(θ)=2θsin(5θ)cotθ over theta in [pi/12,pi/6] θ[π12,π6]?

1 Answer
Jun 2, 2018

approx 1.765881.76588

Explanation:

We have given
r(theta)=2theta*sin(5theta)-cot(5theta)r(θ)=2θsin(5θ)cot(5θ)
then
r'(theta)=2sin(5theta)+10cos(5theta)-1/sin^2(theta)
and we get

int_(pi/12)^(pi/6)sqrt((2theta*sin(5theta)-cot(theta))^2+(2sin(5theta)+10cos(5theta)-1/sin(theta)^2)^2)d theta
I have found only a numerical value of that integral
approx 1.76588