Let $f(x) = \int_{1}^{x} \sin^2 \left(\frac{t}{2}\right) dt$. Then the value of $\lim_{x \to 0} \frac{f(\pi + x) - f(\pi)}{x}$ is equal to:
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Don't waste time actually integrating the function! Most calculus problems involving a limit of an integral are testing your knowledge of the Fundamental Theorem of Calculus.