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Ch. 5 - Integration
5์žฅ, ๋ฌธ์ œ 5.3.111c

Zero net area Consider the function ฦ’(๐“) = ๐“ยฒ โ€• 4๐“ .                                                                                                                                       
                                                                                                                                                                                     c) In general, for the function ฦ’(๐“) = ๐“ยฒ โ€• a๐“, where a > 0, for what value of b > 0 (as a function of a) is โˆซโ‚€แต‡ ฦ’(๐“) d๐“ = 0 ? 

๊ฒ€์ฆ๋œ ๋‹จ๊ณ„๋ณ„ ์•ˆ๋‚ด
1
Start by writing down the integral you need to solve: \(\int_0^b (x^2 - a x) \, dx = 0\), where \(a > 0\) and \(b > 0\).
Compute the indefinite integral of the function \(f(x) = x^2 - a x\). The antiderivative is \(\int (x^2 - a x) \, dx = \frac{x^3}{3} - \frac{a x^2}{2} + C\).
Evaluate the definite integral from 0 to \(b\) using the antiderivative: \(\left[ \frac{x^3}{3} - \frac{a x^2}{2} \right]_0^b = \frac{b^3}{3} - \frac{a b^2}{2} - \left(0\right)\).
Set the definite integral equal to zero to find \(b\): \(\frac{b^3}{3} - \frac{a b^2}{2} = 0\).
Factor the equation to solve for \(b\): \(b^2 \left( \frac{b}{3} - \frac{a}{2} \right) = 0\). Since \(b > 0\), solve \(\frac{b}{3} - \frac{a}{2} = 0\) for \(b\) to express \(b\) as a function of \(a\).

๋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:
3m
๋„์›€์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 Integral and Net Area

The definite integral of a function over an interval represents the net area between the function's graph and the x-axis. Positive areas above the x-axis add to the integral, while areas below subtract. When the integral equals zero, the positive and negative areas cancel out, resulting in zero net area.
์ถ”์ฒœ ์˜์ƒ:
๊ฐ€์ด๋“œ ์ฝ”์Šค
05:43
Definition of the Definite Integral

Finding the Integral of a Quadratic Function

To evaluate the integral of a quadratic function like ฦ’(x) = xยฒ - a x, you apply the power rule for integration term-by-term. This involves increasing the exponent by one and dividing by the new exponent, then applying limits to find the definite integral value as a function of the upper limit b.
์ถ”์ฒœ ์˜์ƒ:
05:11
Integrals of General Exponential Functions

Solving for the Upper Limit to Achieve Zero Net Area

Setting the definite integral equal to zero and solving for the upper limit b involves forming an equation from the integral expression and isolating b. This process finds the point where the accumulated positive and negative areas balance, which depends on the parameter a in the function.
์ถ”์ฒœ ์˜์ƒ:
05:23
Finding Area Between Curves on a Given Interval
๊ด€๋ จ ์‹ค์ฒœ
๊ต๊ณผ์„œ ์งˆ๋ฌธ

Working with area functions Consider the function ฦ’ and its graph.

(c) Sketch a graph of A, for 0 โ‰ค ๐“ โ‰ค 10 , without a scale on the y-axis.


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๊ต๊ณผ์„œ ์งˆ๋ฌธ

{Use of Tech} Approximating definite integrals Complete the following steps for the given integral and the given value of n. 

(c) Calculate the left and right Riemann sums for the given value of n.


โˆซโ‚ƒโถ (1โ€•2๐“) d๐“ ; n = 6

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

Use Table 5.6 to evaluate the following definite integrals.                                                                                                                    

 (c) โˆซโ‚ƒโˆšโ‚‚^โถ d๐“/(๐“ยฒ โ€•9)

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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).

(c) Use geometry to find the displacement of the object between t = 2 and t = 5.

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

{Use of Tech} Approximating definite integrals Complete the following steps for the given integral and the given value of n. 

(c) Calculate the left and right Riemann sums for the given value of n.

โˆซโ‚โท 1/๐“ d๐“ ; n = 6

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๊ต๊ณผ์„œ ์งˆ๋ฌธ

{Use of Tech} Approximating definite integrals Complete the following steps for the given integral and the given value of n. 

(c) Calculate the left and right Riemann sums for the given value of n.


โˆซโ‚€^ฯ€/2 cos ๐“ d๐“ ; n = 4

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