\(\int\limits^{\frac{\pi}{3}}_0\frac{tanxdx}{\sqrt{1-ln^2\left(cosx\right)}}\)
\(\int\limits^{\frac{\pi}{3}}_0\frac{tanxdx}{\sqrt{1-ln^2\left(cosx\right)}}\)
\(\int\limits^{pi/2}_0\frac{sinx}{\left(sinx+\sqrt{3}cosx\right)^2}dx\)
\(\int\limits^{\frac{\pi}{3}}_0\frac{sinx}{cosx\sqrt{3+sin^2x}}dx\)
\(\int\limits^{ln8}_0\frac{e^x}{1+\sqrt{3e^x+1}}dx\)
Hãy chỉ ra kết quả nào dưới đây đúng :
a) \(\int\limits^{\dfrac{\pi}{2}}_0\sin xdx+\int\limits^{\dfrac{3\pi}{2}}_{\dfrac{\pi}{2}}\sin xdx+\int\limits^{2\pi}_{\dfrac{3\pi}{2}}\sin xdx=0\)
b) \(\int\limits^{\dfrac{\pi}{2}}_0\left(\sqrt[3]{\sin x}-\sqrt[3]{\cos x}\right)dx=0\)
c) \(\int\limits^{\dfrac{1}{2}}_{-\dfrac{1}{2}}\ln\dfrac{1-x}{1+x}dx=0\)
d) \(\int\limits^2_0\left(\dfrac{1}{1+x+x^2+x^3}+1\right)dx=0\)
Tính các tích phân sau
1.I=\(\int\limits^{\frac{\Pi}{4}}_0\) (x+1)sin2xdx
2.I=\(\int\limits^2_1\frac{x^2+3x+1}{x^2+x}dx\)
3.I=\(\int\limits^2_1\frac{x^2-1}{x^2}lnxdx\)
4. I=\(\int\limits^1_0x\sqrt{2-x^2}dx\)
5.I=\(\int\limits^1_0\frac{\left(x+1\right)^2}{x^2+1}dx\)
6. I=\(\int\limits^5_1\frac{dx}{1+\sqrt{2x-1}}\)
7. I=\(\int\limits^3_1\frac{1+ln\left(x+1\right)}{x^2}dx\)
8.I=\(\int\limits^1_0\frac{x^3}{x^4+3x^2+2}dx\)
9. I=\(\int\limits^{\frac{\Pi}{4}}_0x\left(1+sin2x\right)dx\)
10. I=\(\int\limits^3_0\frac{x}{\sqrt{x+1}}dx\)
Chỉ mình câu tích phân này với !!
\(\int\limits^{pi/2}_0\left(\frac{1}{cos^2\left(sinx\right)}-tan^2\left(cosx\right)\right)dx\)
Tính các tích phân sau :
a) \(\int\limits^1_0\left(y-1\right)^2\sqrt{y}dy\), đặt \(t=\sqrt{y}\)
b) \(\int\limits^2_1\left(x^2+1\right)\sqrt[3]{\left(z-1\right)^2}dz\), đặt \(u=\sqrt[3]{z-1}\)
c) \(\int\limits^e_1\dfrac{\sqrt{4+5\ln x}}{x}dx\)
d) \(\int\limits^{\dfrac{\pi}{2}}_0\left(\cos^5\varphi-\sin^5\varphi\right)d\varphi\)
e) \(\int\limits^{\pi}_0\cos^3\alpha\cos3\alpha d\alpha\)
Câu a)
Đặt \(y=\sqrt{t}\Rightarrow I_1=\int ^{1}_{0}(y-1)^2\sqrt{y}dy=\int ^{1}_{0}(t^2-1)^2td(t^2)\)
\(\Leftrightarrow I_1=2\int^{1}_{0}(t^2-1)^2t^2dt=2\int ^{1}_{0}(t^6-2t^4+t^2)dt\)
\(=2\left.\begin{matrix} 1\\ 0\end{matrix}\right|\left ( \frac{t^7}{7}-\frac{2t^5}{5}+\frac{t^3}{3} \right )=\frac{16}{105}\)
b) Đặt \(u=\sqrt[3]{z-1}\Rightarrow z=u^3+1\Rightarrow I_2=\int ^{1}_{0}[(u^3+1)^2+1]u^2d(u^3+1)\)
\(\Leftrightarrow I_2=3\int ^{1}_{0}[(u^3+1)^2+1]u^4du=3\int ^{1}_{0}(u^{10}+2u^7+2u^4)du\)
\(=3\left.\begin{matrix} 1\\ 0\end{matrix}\right|\left ( \frac{x^{11}}{11}+\frac{x^8}{4}+\frac{2x^5}{5} \right )=\frac{489}{220}\)
c) Ta có:
\(I_3=\int ^{e}_{1}\frac{\sqrt{4+5\ln x}}{x}dx=\int ^{e}_{1}\sqrt{4+5\ln x}d(\ln x)\)
Đặt \(\sqrt{4+5\ln x}=t\Rightarrow I_3=\int ^{3}_{2}td\left (\frac{t^2-4}{5}\right)=\frac{2}{5}\int ^{3}_{2}t^2dt=\frac{38}{15}\)
d)
Xét \(\int ^{\frac{\pi}{2}}_{0}\cos ^5xdx=\int ^{\frac{\pi}{2}}_{0}\cos ^4xd(\sin x)=\int ^{\frac{\pi}{2}}_{0}(1-\sin ^2x)^2d(\sin x)\)
\(=\int ^{1}_{0}(1-t^2)^2dt\)
Xét \(\int ^{\frac{\pi}{2}}_{0}\sin ^5xdx=-\int ^{\frac{\pi}{2}}_{0}\sin ^4xd(\cos x)=-\int ^{\frac{\pi}{2}}_{0}(1-\cos ^2x)^2d(\cos x)=\int ^{1}_{0}(1-t^2)^2dt\)
Do đó \(\int ^{\frac{\pi}{2}}_{0}(\cos ^5x-\sin ^5x)dx=0\)
e)
Có \(\int \cos ^3x\cos 3xdx=\int \cos 3x\left ( \frac{3\cos x+\cos 3x}{4} \right )dx=\frac{1}{4}\int \cos ^23xdx+\frac{3}{4}\int \cos x\cos 3xdx\)
\(=\frac{1}{8}\int (1+\cos 6x)dx+\frac{3}{8}\int (\cos 4x+\cos 2x)dx\)
\(=\frac{1}{8}\int (1+\cos 6x)dx+\frac{3}{8}\int (\cos 4x+\cos 2x)dx=\frac{x}{8}+\frac{\sin 6x}{48}+\frac{3\sin 4x}{32}+\frac{3\sin 2x}{16}\)
Suy ra \(\int ^{\pi}_{0}\cos ^3x\cos 3xdx=\frac{\pi}{8}\)
Tính các tích phân sau :
a) \(\int\limits^1_0\left(y^3+3y^2-2\right)dy\)
b) \(\int\limits^4_1\left(t+\dfrac{1}{\sqrt{t}}-\dfrac{1}{t^2}\right)dt\)
c) \(\int\limits^{\dfrac{\pi}{2}}_0\left(2\cos x-\sin2x\right)dx\)
d) \(\int\limits^1_0\left(3^s-2^s\right)^2ds\)
e) \(\int\limits^{\dfrac{\pi}{3}}_0\cos3xdx+\int\limits^{\dfrac{3\pi}{2}}_0\cos3xdx+\int\limits^{\dfrac{5\pi}{2}}_{\dfrac{3\pi}{2}}\cos3xdx\)
g) \(\int\limits^3_0\left|x^2-x-2\right|dx\)
h) \(\int\limits^{\dfrac{5\pi}{4}}_{\pi}\dfrac{\sin x-\cos x}{\sqrt{1+\sin2x}}dx\)
i) \(\int\limits^4_0\dfrac{4x-1}{\sqrt{2x+1}+2}dx\)
Câu nào mình biết thì mình làm nha.
1) Đổi thành \(\dfrac{y^4}{4}+y^3-2y\) rồi thế số.KQ là \(\dfrac{-3}{4}\)
2) Biến đổi thành \(\dfrac{t^2}{2}+2\sqrt{t}+\dfrac{1}{t}\) và thế số.KQ là \(\dfrac{35}{4}\)
3) Biến đổi thành 2sinx + cos(2x)/2 và thế số.KQ là 1
\(\int\limits^{\frac{\pi}{2}}_0\frac{Cosx}{1+sin^2x}\)
\(\int\limits^{\frac{\pi}{2}}_0\frac{cosx}{1+sin^2x}dx=\int\limits^{\frac{\pi}{2}}_0\frac{d\left(sinx\right)}{1+sin^2x}=arctan\left(sinx\right)|^{\frac{\pi}{2}}_0=\frac{\pi}{4}\)