\(=\int\limits^{\dfrac{\pi}{3}}_{\dfrac{\pi}{4}}\dfrac{1-2sin^2x}{sin^2x}dx=\int\limits^{\dfrac{\pi}{3}}_{\dfrac{\pi}{4}}\left(\dfrac{1}{sin^2x}-2\right)dx\)
\(=\left(-cotx-2x\right)|^{\dfrac{\pi}{3}}_{\dfrac{\pi}{4}}=...\)
\(=\int\limits^{\dfrac{\pi}{3}}_{\dfrac{\pi}{4}}\dfrac{1-2sin^2x}{sin^2x}dx=\int\limits^{\dfrac{\pi}{3}}_{\dfrac{\pi}{4}}\left(\dfrac{1}{sin^2x}-2\right)dx\)
\(=\left(-cotx-2x\right)|^{\dfrac{\pi}{3}}_{\dfrac{\pi}{4}}=...\)
a) \(\int_{\dfrac{\pi}{8}}^{\dfrac{2\pi}{8}}\)\(\dfrac{dx}{sin^2xcos^2x}\)
b) \(\int_{\dfrac{\pi}{6}}^{\dfrac{\pi}{3}}\)\(\dfrac{cos2xdx}{sin^2xcos^2x}\)
c) \(\int_0^{\dfrac{\pi}{3}}\)\(\dfrac{cos3x}{cosx}\)dx
\(\int_{\dfrac{\pi}{4}}^{\dfrac{\pi}{3}}\)\(\dfrac{2cos2x+5}{sin^2x}dx\)
\(\int_0^{\dfrac{\pi}{4}}\)\(\dfrac{cos2x-3sin^2x}{cos^2x}dx\)
\(\int_0^{\dfrac{\pi}{6}}\)\(\dfrac{1-sin2x+cos2x}{sinx-cos2x}dx\)
Tính tích phân sau:
\(I=\int_0^{\pi}\dfrac{x.sinx}{sin^2x+3}dx\)
Tính tích phân
\(\int\limits^{\dfrac{\pi}{4}}_{\dfrac{-\pi}{4}}\dfrac{\sin x}{\sqrt{1+x^2}+x}dx\)
\(\int_0^{\dfrac{\pi}{4}}\) \(\dfrac{3sin^2x-4cos^2x}{cos^2x}dx\)
Tính tích phân \(\int_{-\pi}^{\pi}\frac{cos^2x}{1+3^{-x}}dx\).
\(\int_0^{\dfrac{\pi}{2}}\)\(\dfrac{1+sin2x}{sinx+cosx}dx\)