題目 Problem Evaluate. (1) limx→1x+73−21−x=(1)‾\displaystyle \lim_{x \to 1} \frac{\sqrt[3]{x+7}-2}{1-\sqrt{x}} = \underline{\quad(1)\quad}x→1lim1−x3x+7−2=(1). (2) limx→∞xtanπxtan−1xπ=(2)‾\displaystyle \lim_{x \to \infty} x \tan \frac{\pi}{x} \tan^{-1} \frac{x}{\pi} = \underline{\quad(2)\quad}x→∞limxtanxπtan−1πx=(2).