Tìm:
a) \(\int4^{x+2}dx;\)
b) \(\int\left(5^{x+2}-e^{x+1}\right)dx\).
Sử dụng định lý Bezout để tìm:
a, Cho f(x) = 2x2 + 3x + a và g(x) = x+2. Tìm giá trị của a để f(x) ⋮ g(x)
b, Cho f(x) = 3x2 + mx - 5 và g(x) = x+2. Tìm giá trị của m để f(x) ⋮ g(x)
a: f(x) chia hết cho g(x)
=>2x^2+4x-x-2+a+2 chia hết cho x+2
=>a+2=0
=>a=-2
b: f(x) chia hết cho g(x)
=>3x^2+6x+(m-6)x+2m-12-2m+7 chia hết cho x+2
=>-2m+7=0
=>m=7/2
Tính các tích phân sau: 1) 2 ln e e x dx ; 2) 1 3 2 0 4 x dx x ; 3) /2 /4 1 tan dx x ; 4) 1 0 x e dx ; 5) 2 1 x xe dx ; 6) 0 1 3 4 dx x ; 7) 2 1 4 4 5 dx x x ; 8) 2 0 ln 1 x dx x (HD: 1 u x ) ĐS: 1) 2 e ; 2) 16 7 5 3 ; 3) ln 2 ; 4) 2
Tính nguyên hàm của:
1, \(\int\)\(\dfrac{x^3}{x-2}dx\)
2, \(\int\)\(\dfrac{dx}{x\sqrt{x^2+1}}\)
3, \(\int\)\((\dfrac{5}{x}+\sqrt{x^3})dx\)
4, \(\int\)\(\dfrac{x\sqrt{x}+\sqrt{x}}{x^2}dx\)
5, \(\int\)\(\dfrac{dx}{\sqrt{1-x^2}}\)
a. \(\int\dfrac{x^3}{x-2}dx=\int\left(x^2+2x+4+\dfrac{8}{x-2}\right)dx=\dfrac{1}{3}x^3+x^2+4x+8ln\left|x-2\right|+C\)
b. \(\int\dfrac{dx}{x\sqrt{x^2+1}}=\int\dfrac{xdx}{x^2\sqrt{x^2+1}}\)
Đặt \(\sqrt{x^2+1}=u\Rightarrow x^2=u^2-1\Rightarrow xdx=udu\)
\(I=\int\dfrac{udu}{\left(u^2-1\right)u}=\int\dfrac{du}{u^2-1}=\dfrac{1}{2}\int\left(\dfrac{1}{u-1}-\dfrac{1}{u+1}\right)du=\dfrac{1}{2}ln\left|\dfrac{u-1}{u+1}\right|+C\)
\(=\dfrac{1}{2}ln\left|\dfrac{\sqrt{x^2+1}-1}{\sqrt{x^2+1}+1}\right|+C\)
c. \(\int\left(\dfrac{5}{x}+\sqrt{x^3}\right)dx=\int\left(\dfrac{5}{x}+x^{\dfrac{3}{2}}\right)dx=5ln\left|x\right|+\dfrac{2}{5}\sqrt{x^5}+C\)
d. \(\int\dfrac{x\sqrt{x}+\sqrt{x}}{x^2}dx=\int\left(x^{-\dfrac{1}{2}}+x^{-\dfrac{3}{2}}\right)dx=2\sqrt{x}-\dfrac{1}{2\sqrt{x}}+C\)
e. \(\int\dfrac{dx}{\sqrt{1-x^2}}=arcsin\left(x\right)+C\)
Cho ∫ - 3 - 1 f ( x ) d x = 1 ; ∫ 3 0 f ( x ) d x = - 2 . Tính ∫ 0 - 1 f ( x ) d x + ∫ - 3 3 f ( x ) d x
A. -1
B. -3
C. 3
D. 1
Cho ∫ 1 2 f ( x ) d x = 2 ; ∫ 1 2 g ( x ) d x = 3 . Tính: I = ∫ 1 2 x + 1 d x + ∫ 1 2 2 f ( x ) d x + ∫ 1 2 3 g ( x ) d x
A. I = 31 2
B. I = 37 2
C. I = 17
D. I = 17 2
Tìm các nguyên hàm sau:
a) \(\int (3x^2-2x-4)dx \)
b) \(\int(\sin3x-\cos4x)dx \)
c) \(\int(e^{-3x}-4^x)dx \)
d) \(\int\ln(x)dx \)
e) \(\int(x.e^x)dx \)
f) \(\int(x+1).\sin(x)dx \)
g) \(\int x.\ln(x)dx \)
\(\int\left(3x^2-2x-4\right)dx=x^3-x^2-4x+C\)
\(\int\left(sin3x-cos4x\right)dx=-\dfrac{1}{3}cos3x-\dfrac{1}{4}sin4x+C\)
\(\int\left(e^{-3x}-4^x\right)dx=-\dfrac{1}{3}e^{-3x}-\dfrac{4^x}{ln4}+C\)
d. \(I=\int lnxdx\)
Đặt \(\left\{{}\begin{matrix}u=lnx\\dv=dx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=\dfrac{dx}{x}\\v=x\end{matrix}\right.\)
\(\Rightarrow u=x.lnx-\int dx=x.lnx-x+C\)
e. Đặt \(\left\{{}\begin{matrix}u=x\\dv=e^xdx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=dx\\v=e^x\end{matrix}\right.\)
\(\Rightarrow I=x.e^x-\int e^xdx=x.e^x-e^x+C\)
f.
Đặt \(\left\{{}\begin{matrix}u=x+1\\dv=sinxdx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=dx\\v=-cosx\end{matrix}\right.\)
\(\Rightarrow I=-\left(x+1\right)cosx+\int cosxdx=-\left(x+1\right)cosx+sinx+C\)
g.
Đặt \(\left\{{}\begin{matrix}u=lnx\\dv=xdx\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}du=\dfrac{dx}{x}\\v=\dfrac{1}{2}x^2\end{matrix}\right.\)
\(\Rightarrow I=\dfrac{1}{2}x^2.lnx-\dfrac{1}{2}\int xdx=\dfrac{1}{2}x^2.lnx-\dfrac{1}{4}x^2+C\)
Tính các tích phân sau:
a) \(\int_0^1x^3\sqrt{1-x^2}dx\)
b) \(\int_1^2\dfrac{dx}{x^2-2x+2}\)
c) \(\int_1^2\dfrac{dx}{\sqrt{4-x^2}}\)
d) \(\int_0^1x\sqrt{x^2+1}dx\)
a.
Đặt \(\sqrt{1-x^2}=u\Rightarrow x^2=1-u^2\Rightarrow xdx=-udu\)
\(\left\{{}\begin{matrix}x=0\Rightarrow u=1\\x=1\Rightarrow u=0\end{matrix}\right.\)
\(\Rightarrow I=\int\limits^0_1\left(1-u^2\right).u.\left(-udu\right)=\int\limits^1_0\left(u^2-u^4\right)du=\left(\dfrac{1}{3}u^3-\dfrac{1}{5}u^5\right)|^1_0\)
\(=\dfrac{2}{15}\)
b.
\(\int\limits^2_1\dfrac{dx}{x^2-2x+2}=\int\limits^2_1\dfrac{dx}{\left(x-1\right)^2+1}\)
Đặt \(x-1=tanu\Rightarrow dx=\dfrac{1}{cos^2u}du\)
\(\left\{{}\begin{matrix}x=1\Rightarrow u=0\\x=2\Rightarrow u=\dfrac{\pi}{4}\end{matrix}\right.\)
\(\Rightarrow I=\int\limits^{\dfrac{\pi}{4}}_0\dfrac{1}{tan^2u+1}.\dfrac{1}{cos^2u}du=\int\limits^{\dfrac{\pi}{4}}_0\dfrac{cos^2u}{cos^2u}du=\int\limits^{\dfrac{\pi}{4}}_0du\)
\(=u|^{\dfrac{\pi}{4}}_0=\dfrac{\pi}{4}\)
c.
\(\int\limits^2_1\dfrac{dx}{\sqrt{4-x^2}}\)
Đặt \(x=2sinu\Rightarrow dx=2cosu.du\)
\(\left\{{}\begin{matrix}x=1\Rightarrow u=\dfrac{\pi}{6}\\x=2\Rightarrow u=\dfrac{\pi}{2}\end{matrix}\right.\)
\(I=\int\limits^{\dfrac{\pi}{2}}_{\dfrac{\pi}{6}}\dfrac{2cosu.du}{\sqrt{4-4sin^2u}}=\int\limits^{\dfrac{\pi}{2}}_{\dfrac{\pi}{6}}\dfrac{2cosu.du}{2cosu}=\int\limits^{\dfrac{\pi}{2}}_{\dfrac{\pi}{6}}du\)
\(=u|^{\dfrac{\pi}{2}}_{\dfrac{\pi}{6}}=\dfrac{\pi}{3}\)
Cho ∫ a d f ( x ) d x = 5 , ∫ b d f ( x ) d x = 2 . Tính ∫ b a f ( x ) d x .
A. 7
B. 3
C. 0
D. -3
Cho ∫ - 1 2 f ( x ) d x = 2 , ∫ - 1 2 g ( x ) d x = - 1 . Tính ∫ - 1 2 [ x + 2 f ( x ) - 3 g ( x ) ] d x
Cho ∫ - 1 1 f ( x ) d x = - 2 ; ∫ 1 3 f ( x ) d x = 5 . Khi đó ∫ - 1 3 2 f ( x ) d x = ?
A. -14
B. 14
C. 12
D. 6