[Toán 12] Tính tích phân $\int_{\frac{\pi}{3}}^{\frac{\pi}{2}} \dfrac{dx}{sinx\sqrt{1 + cosx}} $

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[TEX]\int_{\frac{\pi}{3}}^{\frac{\pi}{2}}\frac{dx}{sinx\sqrt{1 + cosx}}[/TEX]


[laTEX]u = \sqrt{1 + cosx} \\ \\ u^2 -1 = cosx \\ \\ -2udu = sinx.dx \\ \\ \int_{\frac{\pi}{3}}^{\frac{\pi}{2}}\frac{dx}{sinx\sqrt{1 + cosx}} = \int_{\frac{\pi}{3}}^{\frac{\pi}{2}}\frac{sinx.dx}{sin^2x.\sqrt{1 + cosx}} \\ \\ \int_{\frac{\pi}{3}}^{\frac{\pi}{2}}\frac{sinx.dx}{(1-cosx)(1+cosx).\sqrt{1 + cosx}} \\ \\ \int_{\sqrt{\frac{3}{2}}}^{1}\frac{-2udu}{(1-u^2+1)(1+u^2-1).u} = \int_{1}^{\sqrt{\frac{3}{2}}}\frac{2du}{(2-u^2)u^2} \\ \\ \int_{1}^{\sqrt{\frac{3}{2}}}\frac{du}{u^2} + \int_{1}^{\sqrt{\frac{3}{2}}}\frac{du}{2-u^2}[/laTEX]
 
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