Solution
= Solution
Integrating gives $b(\theta_2)-b(\theta_1)\le-(1-\sqrt\gamma)L$. Risk at the endpoints implies $|b(\theta_i)|\le\sqrt\gamma$, so the left side is at least $-2\sqrt\gamma$. Hence $L\le2\sqrt\gamma/(1-\sqrt\gamma)$.
= Solution
Integrating gives $b(\theta_2)-b(\theta_1)\le-(1-\sqrt\gamma)L$. Risk at the endpoints implies $|b(\theta_i)|\le\sqrt\gamma$, so the left side is at least $-2\sqrt\gamma$. Hence $L\le2\sqrt\gamma/(1-\sqrt\gamma)$.