[toán 12]Tích phân hàm số lượng giác

N

nguyenbahiep1

[TEX]I=\int_{0}^{\frac{\pi }{4}}\frac{sinxcosx}{cos2x + sin2x}dx[/TEX]


[laTEX]I= \frac{1}{2}\int_{0}^{\frac{\pi }{4}}\frac{sin2x}{cos2x + sin2x}dx \\ \\ \frac{1}{8}\int_{0}^{\frac{\pi }{4}}\frac{2(cos2x+sin2x) - (2cos2x-2sin2x)}{cos2x + sin2x}dx \\ \\ \frac{1}{4}\int_{0}^{\frac{\pi }{4}}dx - \frac{1}{8}\int_{0}^{\frac{\pi }{4}}\frac{ 2cos2x-2sin2x}{cos2x + sin2x}dx \\ \\ \frac{x}{4} \big|_{0}^{\frac{\pi }{4}} - \frac{1}{8}ln|cos2x+sin2x| \big|_0^{\frac{\pi }{4}}[/laTEX]
 
Top Bottom