Finding Area Bounded by x^2 & 2x - x^2

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Discussion Overview

The discussion revolves around finding the area bounded by the curves defined by the equations \(y = x^2\) and \(y = 2x - x^2\). Participants explore the mathematical steps involved in setting up the integral for this area, including determining the correct limits and the order of subtraction in the integral.

Discussion Character

  • Mathematical reasoning
  • Homework-related
  • Conceptual clarification

Main Points Raised

  • One participant initiates the discussion by stating the equations of the curves and attempts to set up the equation \(x^2 = 2x - x^2\) to find the intersection points.
  • Another participant repeats the initial steps and questions the correct interpretation of "Right - left" in the context of integration with respect to \(x\).
  • A participant suggests using the "Top - Bottom" method for setting up the integral, proposing the expression \(\int^1_0 x^2 - (2x - x^2) \, dx\).
  • Another participant agrees with the "Top - Bottom" approach but raises a concern about ensuring the correct identification of the top and bottom functions, suggesting evaluating both functions at a point within the limits to confirm which is greater.
  • A final comment emphasizes the importance of drawing a diagram to aid in understanding the problem.

Areas of Agreement / Disagreement

Participants generally agree on the method of using integration to find the area, but there is some uncertainty regarding the correct setup of the integral and the identification of the top and bottom functions. The discussion remains unresolved on these specific points.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the curves' behavior and the need for clarity on which function is on top within the integration limits. The mathematical steps leading to the integral setup are also not fully resolved.

shamieh
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Find the area bounded by the curves $$y = x^2[/math] and [math]y = 2x - x^2$$so
$$
x^2 = 2x - x^2$$
$$
2x - x^2 - x^2 = 2x - 2x^2$$

So then would I factor out a 2 and get
$$
2x(x - 1)$$
$$
x = 1$$

So the $$\int ^1_0 Right - left \, dx$$
 
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shamieh said:
Find the area bounded by the curves $$y = x^2[/math] and [math]y = 2x - x^2$$so
$$
x^2 = 2x - x^2$$
$$
2x - x^2 - x^2 = 2x - 2x^2$$

So then would I factor out a 2 and get
$$
2x(x - 1)$$
$$
x = 1$$

So the $$\int ^1_0 Right - left \, dx$$

The "Right" and "Left" is if you're doing an integral with respect to $y$. But you're integrating w.r.t. $x$. So it's what minus what?
 
Top - Bottom ?So would i get $$\int^1_0 x^2 - (2x -x ^2) dx$$
 
shamieh said:
Top - Bottom ?So would i get $$\int^1_0 x^2 - (2x -x ^2) dx$$

Yes, it is top minus bottom, but are you sure you have chosen correctly with regards to which is top and which is bottom? If you are unsure, pick an $x$-value inside the limits of integration and evaluate both functions to see which gives the greater value.
 
WORD OF GOD:

Always draw a diagram.
 

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