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How do you evaluate ∫0∞e−xdx\int_0^\infty e^{-x} dx∫0∞​e−xdx?

  1. Express as a limit: lim⁡b→∞∫0be−xdx\lim_{b \to \infty} \int_0^b e^{-x} dxlimb→∞​∫0b​e−xdx. 2) Evaluate the integral: lim⁡b→∞[−e−x]0b=lim⁡b→∞(−e−b+e0)\lim_{b \to \infty} [-e^{-x}]_0^b = \lim_{b \to \infty} (-e^{-b} + e^0)limb→∞​[−e−x]0b​=limb→∞​(−e−b+e0). 3) Evaluate the limit: lim⁡b→∞(−e−b+1)=1\lim_{b \to \infty} (-e^{-b} + 1) = 1limb→∞​(−e−b+1)=1. 4) The integral converges to 1.
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How do you evaluate ∫0∞e−xdx\int_0^\infty e^{-x} dx∫0∞​e−xdx?

  1. Express as a limit: lim⁡b→∞∫0be−xdx\lim_{b \to \infty} \int_0^b e^{-x} dxlimb→∞​∫0b​e−xdx. 2) Evaluate the integral: lim⁡b→∞[−e−x]0b=lim⁡b→∞(−e−b+e0)\lim_{b \to \infty} [-e^{-x}]_0^b = \lim_{b \to \infty} (-e^{-b} + e^0)limb→∞​[−e−x]0b​=limb→∞​(−e−b+e0). 3) Evaluate the limit: lim⁡b→∞(−e−b+1)=1\lim_{b \to \infty} (-e^{-b} + 1) = 1limb→∞​(−e−b+1)=1. 4) The integral converges to 1.

How do you evaluate ∫1∞1x2dx\int_1^\infty \frac{1}{x^2} dx∫1∞​x21​dx?

  1. Express as a limit: lim⁡b→∞∫1b1x2dx\lim_{b \to \infty} \int_1^b \frac{1}{x^2} dxlimb→∞​∫1b​x21​dx. 2) Evaluate the integral: lim⁡b→∞[−1x]1b=lim⁡b→∞(−1b+1)\lim_{b \to \infty} [-\frac{1}{x}]_1^b = \lim_{b \to \infty} (-\frac{1}{b} + 1)limb→∞​[−x1​]1b​=limb→∞​(−b1​+1). 3) Evaluate the limit: lim⁡b→∞(−1b+1)=1\lim_{b \to \infty} (-\frac{1}{b} + 1) = 1limb→∞​(−b1​+1)=1. 4) The integral converges to 1.

How do you evaluate ∫011xdx\int_0^1 \frac{1}{\sqrt{x}} dx∫01​x​1​dx?

  1. Express as a limit: lim⁡a→0+∫a11xdx\lim_{a \to 0^+} \int_a^1 \frac{1}{\sqrt{x}} dxlima→0+​∫a1​x​1​dx. 2) Evaluate the integral: lim⁡a→0+[2x]a1=lim⁡a→0+(2−2a)\lim_{a \to 0^+} [2\sqrt{x}]_a^1 = \lim_{a \to 0^+} (2 - 2\sqrt{a})lima→0+​[2x​]a1​=lima→0+​(2−2a​). 3) Evaluate the limit: lim⁡a→0+(2−2a)=2\lim_{a \to 0^+} (2 - 2\sqrt{a}) = 2lima→0+​(2−2a​)=2. 4) The integral converges to 2.

How do you evaluate ∫1∞1xdx\int_1^\infty \frac{1}{x} dx∫1∞​x1​dx?

  1. Express as a limit: lim⁡b→∞∫1b1xdx\lim_{b \to \infty} \int_1^b \frac{1}{x} dxlimb→∞​∫1b​x1​dx. 2) Evaluate the integral: lim⁡b→∞[ln⁡∣x∣]1b=lim⁡b→∞(ln⁡(b)−ln⁡(1))\lim_{b \to \infty} [\ln|x|]_1^b = \lim_{b \to \infty} (\ln(b) - \ln(1))limb→∞​[ln∣x∣]1b​=limb→∞​(ln(b)−ln(1)). 3) Evaluate the limit: lim⁡b→∞(ln⁡(b)−0)=∞\lim_{b \to \infty} (\ln(b) - 0) = \inftylimb→∞​(ln(b)−0)=∞. 4) The integral diverges.

How do you evaluate ∫−∞0xexdx\int_{-\infty}^0 xe^x dx∫−∞0​xexdx?

  1. Express as a limit: lim⁡a→−∞∫a0xexdx\lim_{a \to -\infty} \int_a^0 xe^x dxlima→−∞​∫a0​xexdx. 2) Integrate by parts: u=x,dv=exdxu=x, dv=e^x dxu=x,dv=exdx, so du=dx,v=exdu=dx, v=e^xdu=dx,v=ex. Then ∫xexdx=xex−∫exdx=xex−ex+C\int xe^x dx = xe^x - \int e^x dx = xe^x - e^x + C∫xexdx=xex−∫exdx=xex−ex+C. 3) Evaluate the integral: lim⁡a→−∞[xex−ex]a0=lim⁡a→−∞[(0−e0)−(aea−ea)]=lim⁡a→−∞[−1−aea+ea]\lim_{a \to -\infty} [xe^x - e^x]_a^0 = \lim_{a \to -\infty} [(0 - e^0) - (ae^a - e^a)] = \lim_{a \to -\infty} [-1 - ae^a + e^a]lima→−∞​[xex−ex]a0​=lima→−∞​[(0−e0)−(aea−ea)]=lima→−∞​[−1−aea+ea]. 4) Evaluate the limit: lim⁡a→−∞[−1−aea+ea]=−1−0+0=−1\lim_{a \to -\infty} [-1 - ae^a + e^a] = -1 - 0 + 0 = -1lima→−∞​[−1−aea+ea]=−1−0+0=−1. 5) The integral converges to -1.

How do you evaluate ∫−∞∞11+x2dx\int_{-\infty}^{\infty} \frac{1}{1+x^2} dx∫−∞∞​1+x21​dx?

  1. Split the integral: ∫−∞∞11+x2dx=∫−∞011+x2dx+∫0∞11+x2dx\int_{-\infty}^{\infty} \frac{1}{1+x^2} dx = \int_{-\infty}^{0} \frac{1}{1+x^2} dx + \int_{0}^{\infty} \frac{1}{1+x^2} dx∫−∞∞​1+x21​dx=∫−∞0​1+x21​dx+∫0∞​1+x21​dx. 2) Express as limits: lim⁡a→−∞∫a011+x2dx+lim⁡b→∞∫0b11+x2dx\lim_{a \to -\infty} \int_a^0 \frac{1}{1+x^2} dx + \lim_{b \to \infty} \int_0^b \frac{1}{1+x^2} dxlima→−∞​∫a0​1+x21​dx+limb→∞​∫0b​1+x21​dx. 3) Evaluate the integral: lim⁡a→−∞[arctan⁡(x)]a0+lim⁡b→∞[arctan⁡(x)]0b=lim⁡a→−∞[arctan⁡(0)−arctan⁡(a)]+lim⁡b→∞[arctan⁡(b)−arctan⁡(0)]\lim_{a \to -\infty} [\arctan(x)]_a^0 + \lim_{b \to \infty} [\arctan(x)]_0^b = \lim_{a \to -\infty} [\arctan(0) - \arctan(a)] + \lim_{b \to \infty} [\arctan(b) - \arctan(0)]lima→−∞​[arctan(x)]a0​+limb→∞​[arctan(x)]0b​=lima→−∞​[arctan(0)−arctan(a)]+limb→∞​[arctan(b)−arctan(0)]. 4) Evaluate the limits: [0−(−π2)]+[π2−0]=π2+π2=π[0 - (-\frac{\pi}{2})] + [\frac{\pi}{2} - 0] = \frac{\pi}{2} + \frac{\pi}{2} = \pi[0−(−2π​)]+[2π​−0]=2π​+2π​=π. 5) The integral converges to π\piπ.

How do you evaluate ∫2∞1x(x−1)dx\int_2^{\infty} \frac{1}{x(x-1)} dx∫2∞​x(x−1)1​dx?

  1. Express as a limit: lim⁡b→∞∫2b1x(x−1)dx\lim_{b \to \infty} \int_2^b \frac{1}{x(x-1)} dxlimb→∞​∫2b​x(x−1)1​dx. 2) Partial fraction decomposition: 1x(x−1)=Ax+Bx−1\frac{1}{x(x-1)} = \frac{A}{x} + \frac{B}{x-1}x(x−1)1​=xA​+x−1B​. Solving gives A=−1A = -1A=−1 and B=1B = 1B=1. So, 1x(x−1)=−1x+1x−1\frac{1}{x(x-1)} = \frac{-1}{x} + \frac{1}{x-1}x(x−1)1​=x−1​+x−11​. 3) Evaluate the integral: lim⁡b→∞∫2b(−1x+1x−1)dx=lim⁡b→∞[−ln⁡∣x∣+ln⁡∣x−1∣]2b=lim⁡b→∞[ln⁡∣x−1x∣]2b=lim⁡b→∞[ln⁡∣b−1b∣−ln⁡∣2−12∣]\lim_{b \to \infty} \int_2^b (\frac{-1}{x} + \frac{1}{x-1}) dx = \lim_{b \to \infty} [-\ln|x| + \ln|x-1|]_2^b = \lim_{b \to \infty} [\ln|\frac{x-1}{x}|]_2^b = \lim_{b \to \infty} [\ln|\frac{b-1}{b}| - \ln|\frac{2-1}{2}|]limb→∞​∫2b​(x−1​+x−11​)dx=limb→∞​[−ln∣x∣+ln∣x−1∣]2b​=limb→∞​[ln∣xx−1​∣]2b​=limb→∞​[ln∣bb−1​∣−ln∣22−1​∣]. 4) Evaluate the limit: lim⁡b→∞[ln⁡∣b−1b∣−ln⁡(12)]=ln⁡(1)−ln⁡(12)=0−(−ln⁡(2))=ln⁡(2)\lim_{b \to \infty} [\ln|\frac{b-1}{b}| - \ln(\frac{1}{2})] = \ln(1) - \ln(\frac{1}{2}) = 0 - (-\ln(2)) = \ln(2)limb→∞​[ln∣bb−1​∣−ln(21​)]=ln(1)−ln(21​)=0−(−ln(2))=ln(2). 5) The integral converges to ln⁡(2)\ln(2)ln(2).

How do you evaluate ∫0∞cos(x)dx\int_0^{\infty} cos(x) dx∫0∞​cos(x)dx?

  1. Express as a limit: lim⁡b→∞∫0bcos(x)dx\lim_{b \to \infty} \int_0^b cos(x) dxlimb→∞​∫0b​cos(x)dx. 2) Evaluate the integral: lim⁡b→∞[sin(x)]0b=lim⁡b→∞(sin(b)−sin(0))\lim_{b \to \infty} [sin(x)]_0^b = \lim_{b \to \infty} (sin(b) - sin(0))limb→∞​[sin(x)]0b​=limb→∞​(sin(b)−sin(0)). 3) Evaluate the limit: lim⁡b→∞(sin(b)−0)\lim_{b \to \infty} (sin(b) - 0)limb→∞​(sin(b)−0). Since sin(b)sin(b)sin(b) oscillates between -1 and 1 as b approaches infinity, the limit does not exist. 4) The integral diverges.

How do you evaluate ∫031x−2dx\int_0^{3} \frac{1}{x-2} dx∫03​x−21​dx?

  1. Split the integral at the discontinuity: ∫031x−2dx=∫021x−2dx+∫231x−2dx\int_0^{3} \frac{1}{x-2} dx = \int_0^{2} \frac{1}{x-2} dx + \int_2^{3} \frac{1}{x-2} dx∫03​x−21​dx=∫02​x−21​dx+∫23​x−21​dx. 2) Express as limits: lim⁡b→2−∫0b1x−2dx+lim⁡a→2+∫a31x−2dx\lim_{b \to 2^-} \int_0^b \frac{1}{x-2} dx + \lim_{a \to 2^+} \int_a^3 \frac{1}{x-2} dxlimb→2−​∫0b​x−21​dx+lima→2+​∫a3​x−21​dx. 3) Evaluate the integral: lim⁡b→2−[ln⁡∣x−2∣]0b+lim⁡a→2+[ln⁡∣x−2∣]a3=lim⁡b→2−[ln⁡∣b−2∣−ln⁡∣−2∣]+lim⁡a→2+[ln⁡∣3−2∣−ln⁡∣a−2∣]=lim⁡b→2−[ln⁡∣b−2∣−ln⁡(2)]+lim⁡a→2+[ln⁡(1)−ln⁡∣a−2∣]\lim_{b \to 2^-} [\ln|x-2|]_0^b + \lim_{a \to 2^+} [\ln|x-2|]_a^3 = \lim_{b \to 2^-} [\ln|b-2| - \ln|-2|] + \lim_{a \to 2^+} [\ln|3-2| - \ln|a-2|] = \lim_{b \to 2^-} [\ln|b-2| - \ln(2)] + \lim_{a \to 2^+} [\ln(1) - \ln|a-2|]limb→2−​[ln∣x−2∣]0b​+lima→2+​[ln∣x−2∣]a3​=limb→2−​[ln∣b−2∣−ln∣−2∣]+lima→2+​[ln∣3−2∣−ln∣a−2∣]=limb→2−​[ln∣b−2∣−ln(2)]+lima→2+​[ln(1)−ln∣a−2∣]. 4) Evaluate the limits: Since lim⁡b→2−ln⁡∣b−2∣=−∞\lim_{b \to 2^-} \ln|b-2| = -\inftylimb→2−​ln∣b−2∣=−∞ and lim⁡a→2+ln⁡∣a−2∣=−∞\lim_{a \to 2^+} \ln|a-2| = -\inftylima→2+​ln∣a−2∣=−∞, both integrals diverge. 5) The integral diverges.

How do you evaluate ∫0∞x(1+x2)2dx\int_0^{\infty} \frac{x}{(1+x^2)^2} dx∫0∞​(1+x2)2x​dx?

  1. Express as a limit: lim⁡b→∞∫0bx(1+x2)2dx\lim_{b \to \infty} \int_0^b \frac{x}{(1+x^2)^2} dxlimb→∞​∫0b​(1+x2)2x​dx. 2) Use u-substitution: Let u=1+x2u = 1+x^2u=1+x2, then du=2xdxdu = 2x dxdu=2xdx, so xdx=12dux dx = \frac{1}{2} duxdx=21​du. The integral becomes 12∫1u2du=12∫u−2du=12[−1u]+C=−12(1+x2)+C\frac{1}{2} \int \frac{1}{u^2} du = \frac{1}{2} \int u^{-2} du = \frac{1}{2} [-\frac{1}{u}] + C = -\frac{1}{2(1+x^2)} + C21​∫u21​du=21​∫u−2du=21​[−u1​]+C=−2(1+x2)1​+C. 3) Evaluate the integral: lim⁡b→∞[−12(1+x2)]0b=lim⁡b→∞[−12(1+b2)−(−12(1+02))]=lim⁡b→∞[−12(1+b2)+12]\lim_{b \to \infty} [-\frac{1}{2(1+x^2)}]_0^b = \lim_{b \to \infty} [-\frac{1}{2(1+b^2)} - (-\frac{1}{2(1+0^2)})] = \lim_{b \to \infty} [-\frac{1}{2(1+b^2)} + \frac{1}{2}]limb→∞​[−2(1+x2)1​]0b​=limb→∞​[−2(1+b2)1​−(−2(1+02)1​)]=limb→∞​[−2(1+b2)1​+21​]. 4) Evaluate the limit: lim⁡b→∞[−12(1+b2)+12]=0+12=12\lim_{b \to \infty} [-\frac{1}{2(1+b^2)} + \frac{1}{2}] = 0 + \frac{1}{2} = \frac{1}{2}limb→∞​[−2(1+b2)1​+21​]=0+21​=21​. 5) The integral converges to 12\frac{1}{2}21​.

What is an improper integral?

An integral where the limits of integration involve infinity or the function becomes unbounded within the interval.

What does it mean for an improper integral to converge?

The limit of the integral approaches a finite value.

What does it mean for an improper integral to diverge?

The limit of the integral approaches infinity or does not exist.

What does 'unbounded' mean in the context of improper integrals?

The function approaches infinity within the integration interval.

What is the role of limits in evaluating improper integrals?

Limits allow us to evaluate integrals with infinite boundaries by approaching infinity.

Define the term 'integrand'.

The function being integrated.

What is a definite integral?

An integral with an upper and lower bound that results in a numerical value.

What is an indefinite integral?

An integral without boundaries.

What is the First Fundamental Theorem of Calculus?

A theorem that allows us to solve definite integrals.

Define the term 'partial fraction'.

Decomposition of a rational function into simpler fractions.

How do you express an improper integral with an upper bound of infinity as a limit?

∫a∞f(x),dx=lim⁡b→∞∫abf(x),dx\int_a^\infty f(x) , dx = \lim_{b \to \infty} \int_a^b f(x) , dx∫a∞​f(x),dx=limb→∞​∫ab​f(x),dx

How do you express an improper integral with a lower bound of negative infinity as a limit?

∫−∞bf(x),dx=lim⁡a→−∞∫abf(x),dx\int_{-\infty}^b f(x) , dx = \lim_{a \to -\infty} \int_a^b f(x) , dx∫−∞b​f(x),dx=lima→−∞​∫ab​f(x),dx

How do you express an improper integral with both bounds being infinity as a limit?

∫−∞∞f(x),dx=lim⁡a→−∞∫acf(x),dx+lim⁡b→∞∫cbf(x),dx\int_{-\infty}^\infty f(x) , dx = \lim_{a \to -\infty} \int_a^c f(x) , dx + \lim_{b \to \infty} \int_c^b f(x) , dx∫−∞∞​f(x),dx=lima→−∞​∫ac​f(x),dx+limb→∞​∫cb​f(x),dx

What is the formula for the integral of 1x\frac{1}{x}x1​?

∫1xdx=ln⁡∣x∣+C\int \frac{1}{x} dx = \ln|x| + C∫x1​dx=ln∣x∣+C

What is the formula for the integral of 1a2+x2\frac{1}{a^2+x^2}a2+x21​?

∫1a2+x2dx=1aarctan⁡(xa)+C\int \frac{1}{a^2+x^2} dx = \frac{1}{a} \arctan(\frac{x}{a}) + C∫a2+x21​dx=a1​arctan(ax​)+C

Give the general form of partial fraction decomposition.

P(x)Q(x)=Ax−a+Bx−b+...\frac{P(x)}{Q(x)} = \frac{A}{x-a} + \frac{B}{x-b} + ...Q(x)P(x)​=x−aA​+x−bB​+...

What is the formula for integration by substitution?

∫f(g(x))g′(x)dx=∫f(u)du\int f(g(x))g'(x)dx = \int f(u)du∫f(g(x))g′(x)dx=∫f(u)du where u=g(x)u=g(x)u=g(x)

What is the formula for the integral of exe^xex?

∫exdx=ex+C\int e^x dx = e^x + C∫exdx=ex+C

What is the formula for the integral of xnx^nxn?

∫xndx=xn+1n+1+C\int x^n dx = \frac{x^{n+1}}{n+1} + C∫xndx=n+1xn+1​+C, where n≠−1n \neq -1n=−1

What is the formula for the integral of sin(x)sin(x)sin(x)?

∫sin(x)dx=−cos(x)+C\int sin(x) dx = -cos(x) + C∫sin(x)dx=−cos(x)+C