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Ch. 5 - Integration
5์žฅ, ๋ฌธ์ œ 5.2.51b

Properties of integrals Use only the fact that โˆซโ‚€โด 3๐“ (4 โ€•๐“) d๐“ = 32, and the definitions and properties of integrals, to evaluate the following integrals, if possible.
(b) โˆซโ‚€โด ๐“(๐“ โ€• 4) d(๐“)

๊ฒ€์ฆ๋œ ๋‹จ๊ณ„๋ณ„ ์•ˆ๋‚ด
1
Step 1: Begin by analyzing the given integral โˆซโ‚€โด ๐“(๐“ โ€• 4) d๐“. Notice that the integrand ๐“(๐“ โ€• 4) can be rewritten as a product of terms. Expand the expression ๐“(๐“ โ€• 4) to simplify it into a polynomial form.
Step 2: Expand the integrand: ๐“(๐“ โ€• 4) = ๐“ยฒ โ€• 4๐“. This simplifies the integral to โˆซโ‚€โด (๐“ยฒ โ€• 4๐“) d๐“.
Step 3: Use the linearity property of integrals to split the integral into two separate integrals: โˆซโ‚€โด (๐“ยฒ โ€• 4๐“) d๐“ = โˆซโ‚€โด ๐“ยฒ d๐“ โ€• โˆซโ‚€โด 4๐“ d๐“.
Step 4: Factor out constants where applicable. For the second term, factor out the constant 4: โˆซโ‚€โด ๐“ยฒ d๐“ โ€• 4โˆซโ‚€โด ๐“ d๐“.
Step 5: Evaluate each integral using the definitions and properties of integrals. Recall that โˆซโ‚€โด 3๐“(4 โ€• ๐“) d๐“ = 32 is given, and use this information to relate the results if necessary. Apply the power rule for integration to compute โˆซโ‚€โด ๐“ยฒ d๐“ and โˆซโ‚€โด ๐“ d๐“.

๋น„์Šทํ•œ ๋ฌธ์ œ์— ๋Œ€ํ•œ ๊ฒ€์ฆ๋œ ์˜์ƒ ๋‹ต๋ณ€:

์ด ์˜์ƒ ํ•ด๋ฒ•์€ ์œ„ ๋ฌธ์ œ์— ๋„์›€์ด ๋œ๋‹ค๊ณ  ํŠœํ„ฐ๋“ค์ด ์ถ”์ฒœํ•œ ๊ฒƒ์ž…๋‹ˆ๋‹ค.
์˜์ƒ ๊ธธ์ด:
2m
๋„์›€์ด ๋˜์—ˆ๋‚˜์š”?

์ฃผ์š” ๊ฐœ๋…

์งˆ๋ฌธ์— ์˜ฌ๋ฐ”๋ฅด๊ฒŒ ๋‹ตํ•˜๊ธฐ ์œ„ํ•ด ๋ฐ˜๋“œ์‹œ ์ดํ•ดํ•ด์•ผ ํ•˜๋Š” ํ•ต์‹ฌ ๊ฐœ๋…๋“ค์€ ๋‹ค์Œ๊ณผ ๊ฐ™์Šต๋‹ˆ๋‹ค.

Definite Integrals

A definite integral represents the signed area under a curve between two points on the x-axis. It is denoted as โˆซโ‚แต‡ f(x) dx, where 'a' and 'b' are the limits of integration. The value of a definite integral can be interpreted as the accumulation of quantities, such as area, over the interval [a, b]. Understanding how to evaluate definite integrals is crucial for solving problems involving areas and accumulated quantities.
์ถ”์ฒœ ์˜์ƒ:
๊ฐ€์ด๋“œ ์ฝ”์Šค
05:43
Definition of the Definite Integral

Properties of Integrals

The properties of integrals, such as linearity, additivity, and the ability to change variables, are essential for simplifying and evaluating integrals. For instance, the linearity property states that โˆซ(c * f(x)) dx = c * โˆซf(x) dx for a constant 'c'. Additionally, the additivity property allows us to split integrals over adjacent intervals, which can be useful in evaluating more complex integrals by breaking them down into simpler parts.
์ถ”์ฒœ ์˜์ƒ:

Integration by Substitution

Integration by substitution is a technique used to simplify the process of evaluating integrals by changing the variable of integration. This method involves substituting a new variable for a function of the original variable, which can make the integral easier to solve. It is particularly useful when dealing with composite functions or when the integrand can be expressed in a simpler form through substitution.
์ถ”์ฒœ ์˜์ƒ:
04:27
Substitution With an Extra Variable
๊ด€๋ จ ์‹ค์ฒœ
๊ต๊ณผ์„œ ์งˆ๋ฌธ

Using properties of integrals Use the value of the first integral I to evaluate the two given integrals. 

I = โˆซโ‚€ยน (๐“ยณ โ€• 2๐“) d๐“ = โ€•3/4

(b) โˆซโ‚โฐ (2๐“โ€•๐“ยณ) d๐“

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Displacement from a velocity graph Consider the velocity function for an object moving along a line (see figure).

(b) Use geometry to find the displacement of the object between t = 0 and t = 2.

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

{Use of Tech} Midpoint Riemann sums with a calculator Consider the following definite integrals.

(b) Evaluate each sum using a calculator with n = 20, 50, and 100. Use these values to estimate the value of the integral.


โˆซโ‚โด 2โˆš๐“ d๐“

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Matching functions with area functions Match the functions ฦ’, whose graphs are given in aโ€• d, with the area functions A (๐“) = โˆซโ‚€หฃ ฦ’(t) dt, whose graphs are given in Aโ€“D.



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๊ต๊ณผ์„œ ์งˆ๋ฌธ

{Use of Tech} Approximating net area The following functions are positive and negative on the given interval.


f(x) = sin 2x on [0,3ฯ€/4]


(b) Approximate the net area bounded by the graph of f and the x-axis on the interval using a left, right, and midpoint Riemann sum with n = 4.

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

{Use of Tech} Approximating definite integrals with a calculator Consider the following definite integrals.

(b) Evaluate each sum using a calculator with n = 20, 50, and 100. Use these values to estimate the value of the integral.


โˆซโ‚€ยน cos โปยน ๐“ d๐“

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