Answer
$$
1
$$
Work Step by Step
We find:
$\frac{\left|\frac{d^{2} y}{d x^{2}}\right|}{\left(\left(\frac{d y}{d x}\right)^{2}+1\right)^{3 / 2}}=\kappa$
$\frac{|\sin x|}{\left(\cos ^{2} x+1\right)^{3 / 2}}=\kappa(x)$
$1=\kappa(\pi / 2)$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.