giải tích phân
giúp mình nhé
cảm ơn.
Đặt [TEX][B]x=-t [/B]\Rightarrow I=\int_{\pi}^{-\pi}\frac{-sin7t+|cost|}{4-sin^2t}(-dt)=\int_{-\pi}^{\pi}\frac{-sin7x+|cosx|}{4-sin^2x}dx \Rightarrow I+I=\int_{-\pi}^{\pi}\frac{2|cosx|}{4-sin^2x}dx=\int_{-\pi}^{\frac{-\pi}{2}}\frac{-2cosx}{4-sin^2x}dx+\int_{\frac{-\pi}{2}}^{\frac{\pi}{2}}\frac{2cosx}{4-sin^2x}dx+\int_{\frac{\pi}{2}}^{\pi}\frac{-2cosx}{4-sin^2x}dx[/TEX]
Đặt
sinx=t