Integration. Where is the mistake? (if there is)

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Homework Help Overview

The discussion revolves around the integration of a function involving trigonometric identities, specifically the integral of tan(x)sec²(x). Participants are evaluating their respective solutions and questioning the correctness of each other's approaches.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are comparing their solutions to the integral and questioning whether both can be correct. There is an exploration of the integration process and potential mistakes in the setup or execution of the integration.

Discussion Status

The discussion includes varying opinions on the correctness of the solutions provided. Some participants assert that one solution is correct while another is almost correct, indicating a nuanced understanding of the differences between the two answers. There is no explicit consensus on a single correct answer, but guidance has been offered regarding the nature of the solutions.

Contextual Notes

Participants are working under the constraints of homework rules, which may limit the depth of their explanations or the completeness of their solutions. There is a focus on identifying mistakes rather than providing final answers.

Sarah00
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Homework Statement


upload_2017-4-17_1-2-37.png


Homework Equations

The Attempt at a Solution


My Solution:
upload_2017-4-17_1-2-59.png


My Friend Solution:
upload_2017-4-17_1-3-22.png
Are we both right?
If not, who is right? and what is the mistake in other's solution!

Thanks![/B]
 
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You are correct. The problem with your friend's solution is the integration itself, what is the integral of tan(x)sec2(x)?
 
Both answers are correct.
 
Sarah00 said:

Homework Statement


View attachment 195086

Homework Equations

The Attempt at a Solution


My Solution:
View attachment 195087

My Friend Solution:
View attachment 195088Are we both right?
If not, who is right? and what is the mistake in other's solution!

Thanks![/B]
Your solution is correct, and your friend's solution is almost correct. Your friend wrote ##\frac{\tan x^2} 2 + C##, but possibly meant to write ##\frac{\tan^2(x)} 2 + C##. Although this is different from what you found, the corrected answer from your friend differs only by a constant from your answer. Note that ##\sec^2(x) = \tan^2(x) + 1##, so ##\frac{\sec^2(x)}{2} = \frac{\tan^2(x)}{2} + \frac 1 2##
 
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