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Ch. 5 - Integration
5์žฅ, ๋ฌธ์ œ 5.5.88

Integrals with sinยฒ ๐“ and cosยฒ ๐“ Evaluate the following integrals.                                                                                                             
                                                                                                                                                                    
 โˆซ sinยฒ ๐“ d๐“

๊ฒ€์ฆ๋œ ๋‹จ๊ณ„๋ณ„ ์•ˆ๋‚ด
1
Step 1: Recognize that the integral involves sinยฒ(๐“). To simplify this, use the trigonometric identity sinยฒ(๐“) = (1 - cos(2๐“)) / 2.
Step 2: Rewrite the integral using the identity: โˆซ sinยฒ(๐“) d๐“ = โˆซ [(1 - cos(2๐“)) / 2] d๐“.
Step 3: Split the integral into two parts: โˆซ [(1/2) - (cos(2๐“)/2)] d๐“ = (1/2) โˆซ 1 d๐“ - (1/2) โˆซ cos(2๐“) d๐“.
Step 4: Evaluate each part separately. For the first term, โˆซ 1 d๐“ = ๐“. For the second term, use the formula for the integral of cos(k๐“): โˆซ cos(k๐“) d๐“ = (1/k) sin(k๐“). Here, k = 2.
Step 5: Combine the results: (1/2)๐“ - (1/4)sin(2๐“) + C, where C is the constant of integration.

๋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

์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.

Trigonometric Identities

Trigonometric identities are equations involving trigonometric functions that are true for all values of the variables. Key identities include the Pythagorean identities, such as sinยฒ(x) + cosยฒ(x) = 1, which can simplify integrals involving sinยฒ(x) and cosยฒ(x). Understanding these identities is crucial for transforming integrals into more manageable forms.
์ถ”์ฒœ ์˜์ƒ:
7:17
Verifying Trig Equations as Identities

Integration Techniques

Integration techniques are methods used to find the integral of a function. Common techniques include substitution, integration by parts, and using trigonometric identities. For integrals involving sinยฒ(x), the power-reduction formula can be particularly useful, allowing the integral to be expressed in terms of simpler functions that are easier to integrate.
์ถ”์ฒœ ์˜์ƒ:
๊ฐ€์ด๋“œ ์ฝ”์Šค
06:18
Integration by Parts for Definite Integrals

Definite and Indefinite Integrals

Definite integrals calculate the area under a curve between two specified limits, while indefinite integrals represent a family of functions and include a constant of integration. Understanding the difference is essential when evaluating integrals, as it affects the final result and the interpretation of the integral in a given context.
์ถ”์ฒœ ์˜์ƒ:
๊ฐ€์ด๋“œ ์ฝ”์Šค
05:43
Definition of the Definite Integral
๊ด€๋ จ ์‹ค์ฒœ
๊ต๊ณผ์„œ ์งˆ๋ฌธ

Area functions from graphs The graph of ฦ’ is given in the figure. A(๐“) = โˆซโ‚€หฃ ฦ’(t) dt and evaluate A(2), A(5), A(8), and A(12).


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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Definite integrals Evaluate the following integrals using the Fundamental Theorem of Calculus


โˆซโ‚โด (๐“ โ€• 2)/โˆš๐“ d๐“

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Indefinite integrals Use a change of variables or Table 5.6 to evaluate the following indefinite integrals. Check your work by differentiating.                                                                                  

                                                                                                                                                                    

 โˆซ ๐“ csc ๐“ยฒ cot ๐“ยฒ d๐“

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Multiple substitutions If necessary, use two or more substitutions to find the following integrals.                                                                                    

                                                                                                                                                                    

  โˆซ ๐“ sinโด ๐“ยฒ cos ๐“ยฒ d๐“ (Hint: Begin with u = ๐“ยฒ, and then use v = sin u .)

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Average values Find the average value of the following functions on the given interval. Draw a graph of the function and indicate the average value.

ฦ’(๐“) = 1/(๐“ยฒ + 1) on [โ€•1, 1]

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Integrals with sinยฒ ๐“ and cosยฒ ๐“ Evaluate the following integrals.                                                                                                             

                                                                                                                                                                    

 โˆซโ‚€^ฯ€/โด cosยฒ 8ฮธ dฮธ

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