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What is u-substitution?

A technique to simplify integrals by introducing a new variable, uu, to transform the integral into a more recognizable form.

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What is u-substitution?

A technique to simplify integrals by introducing a new variable, uu, to transform the integral into a more recognizable form.

What is an integrand?

The function being integrated in an integral.

What is an indefinite integral?

An integral without specified upper and lower limits, resulting in a function plus a constant of integration.

What is a definite integral?

An integral with specified upper and lower limits, resulting in a numerical value.

What is back-substitution?

The process of replacing the variable uu with its original expression in terms of xx after integration.

Define limits of integration.

The upper and lower bounds of a definite integral, which specify the interval over which the integration is performed.

What is a composite function?

A function formed by substituting one function into another, typically in the form f(g(x))f(g(x)).

What is the constant of integration?

A constant term, denoted as CC, added to the antiderivative of a function to represent the family of all possible antiderivatives.

Define antiderivative.

A function whose derivative is equal to a given function. If F(x)=f(x)F'(x) = f(x), then F(x)F(x) is an antiderivative of f(x)f(x).

What does it mean to evaluate an integral?

To find the antiderivative of the integrand and, for definite integrals, compute its value at the upper and lower limits of integration.

What is the general form for u-substitution?

f(g(x))cdotg(x),dx=f(u),du\int f(g(x)) cdot g'(x) , dx = \int f(u) , du, where u=g(x)u = g(x) and du=g(x),dxdu = g'(x) , dx.

If u=g(x)u = g(x), what is dudu?

du=g(x),dxdu = g'(x) , dx

How to transform limits of integration with u-substitution?

If the original limits are x=ax=a and x=bx=b, then the new limits are u=g(a)u=g(a) and u=g(b)u=g(b).

What is the integral of cos(u)\cos(u) with respect to uu?

cos(u),du=sin(u)+C\int \cos(u) , du = \sin(u) + C

What is the integral of unu^n with respect to uu, where n1n \neq -1?

un,du=un+1n+1+C\int u^n , du = \frac{u^{n+1}}{n+1} + C

What is the integral of 1u\frac{1}{u} with respect to uu?

1u,du=lnu+C\int \frac{1}{u} , du = \ln|u| + C

What is the derivative of xnx^n?

ddxxn=nxn1\frac{d}{dx}x^n = nx^{n-1}

What is the derivative of a constant?

ddxc=0\frac{d}{dx}c = 0

What is the chain rule?

ddx[f(g(x))]=f(g(x))g(x)\frac{d}{dx}[f(g(x))] = f'(g(x)) * g'(x)

What is the integral of 2xcos(x2)2xcos(x^2)?

2xcos(x2)dx=sin(x2)+C\int 2xcos(x^2) dx = sin(x^2) + C

How to evaluate 2xcos(x2),dx\int 2x \cos(x^2) , dx using u-substitution?

  1. Let u=x2u = x^2. 2. Find du=2x,dxdu = 2x , dx. 3. Rewrite the integral as cos(u),du\int \cos(u) , du. 4. Evaluate to get sin(u)+C\sin(u) + C. 5. Back-substitute to get sin(x2)+C\sin(x^2) + C.

How to evaluate 122x(x2+1)2,dx\int_{1}^{2} \frac{2x}{(x^2+1)^2} , dx using u-substitution?

  1. Let u=x2+1u = x^2 + 1. 2. Find du=2x,dxdu = 2x , dx. 3. Change limits: when x=1x=1, u=2u=2; when x=2x=2, u=5u=5. 4. Rewrite the integral as 251u2,du\int_{2}^{5} \frac{1}{u^2} , du. 5. Evaluate to get [1u]25\left[-\frac{1}{u}\right]_{2}^{5}. 6. Calculate the definite integral: (15)(12)=310(-\frac{1}{5}) - (-\frac{1}{2}) = \frac{3}{10}.

Steps for u-substitution with indefinite integrals?

  1. Identify the inner function. 2. Choose uu. 3. Find dudu. 4. Rewrite the integral in terms of uu. 5. Evaluate the integral. 6. Back-substitute.

Steps for u-substitution with definite integrals (changing limits)?

  1. Identify the inner function. 2. Choose uu. 3. Find dudu. 4. Change the limits of integration. 5. Rewrite the integral in terms of uu. 6. Evaluate the integral.

Steps for u-substitution with definite integrals (substituting back)?

  1. Identify the inner function. 2. Choose uu. 3. Find dudu. 4. Rewrite the integral in terms of uu. 5. Evaluate the integral. 6. Back-substitute. 7. Evaluate with original limits.

How do you choose 'u' for u-substitution?

Look for an inner function whose derivative is also present in the integral. Common choices include expressions within parentheses, under radicals, or in exponents.

How do you rewrite the integral with u-substitution?

Replace the chosen expression with 'u' and replace 'dx' with an expression involving 'du'. Ensure the entire integral is in terms of 'u'.

What do you do after integrating with respect to 'u'?

For indefinite integrals, substitute back the original expression in terms of 'x' for 'u'. For definite integrals, either change the limits of integration or substitute back before evaluating.

How do you handle constants when finding 'du'?

Isolate 'dx' by dividing by any constants that appear when finding 'du'. Include these constants when rewriting the integral.

What should you do if the derivative of 'u' doesn't exactly match the remaining integrand?

Manipulate the equation for 'du' to match the remaining integrand by multiplying or dividing by constants. Adjust the integral accordingly.