Q82·Section II (Mathematics)·82 of 180Calculus of variations — polar arc lengthThe extremal of the functional I(r(θ))=∫θ0θr2+r′2 dθI(r(\theta))=\int_{\theta_0}^\theta\sqrt{r^2+r'^2}\,d\thetaI(r(θ))=∫θ0θr2+r′2dθ, r′=drdθr'=\frac{dr}{d\theta}r′=dθdr, is: OptionsAa catenaryBa cycloidCa straight lineDan arc of the great circlePick an option to check your answer.Show answerShow solution Report a problem with this question← Q81All questionsQ83 →Keyboard: A–D answer · S solution · ←/→ previous/next