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摘要: 计算:\(\int_{-\pi}^{\pi} \frac{x\sin^3x}{1+e^x}dx\) \[ \int_{-\pi}^{\pi} \frac{x\sin^3x}{1+e^x}dx \\ =\int_{-\pi}^{0} \frac{x\sin^3x}{1+e^x}dx +\int_{0} 阅读全文
posted @ 2021-11-24 11:00 nekko 阅读(147) 评论(0) 推荐(0)
摘要: 计算:\(\int_{0}^{1}\frac{dx}{(x+1)\sqrt{x^2+1}}\) 试试散装复变 \[ \int_{0}^{1}\frac{dx}{(x+1)\sqrt{x^2+1}} \\ =\int_{0}^{\frac{\pi}{4}}\frac{\sec^2tdt}{(1+\ta 阅读全文
posted @ 2021-11-24 10:35 nekko 阅读(297) 评论(0) 推荐(1)
摘要: 求:\(\lim_{x \to 0^+}\frac{x \ln \sin x-\sin x \ln x}{x^3\ln x}\) \[ \lim_{x \to 0^+}\frac{x \ln \sin x-\sin x \ln x}{x^3\ln x} \\ =\lim_{x \to 0^+}\fr 阅读全文
posted @ 2021-11-24 09:14 nekko 阅读(165) 评论(0) 推荐(0)
摘要: 已知:\(\lim_{x \to 0}\left(\frac{a}{x^2}+\frac{b\int_0^{x}e^{-t^2}dt}{x^3}\right)\) 存在 求 \(a,b\) 的关系 \[ \lim_{x \to 0}\left(\frac{a}{x^2}+\frac{b\int_0^ 阅读全文
posted @ 2021-11-24 08:33 nekko 阅读(69) 评论(0) 推荐(0)