Definite Integral of x^2*sqrt(7x+9) from 0 to 1 - Need Help!

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Discussion Overview

The discussion centers around finding the definite integral of the function x²√(7x + 9) from 0 to 1. Participants seek assistance with the integration process, exploring substitution methods.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant requests help with the definite integral ∫ (x²)√(7x + 9) dx from 0 to 1.
  • Another participant suggests using the substitution y = √(7x + 9) to simplify the integral.
  • A subsequent participant asks for more detailed guidance on how to express dx and x in terms of y for the substitution.
  • Further clarification is sought regarding the relationship between dx and dy, as well as how to express x² in terms of y.
  • One participant indicates they have understood the approach after receiving help.

Areas of Agreement / Disagreement

The discussion does not present any explicit agreement or disagreement, as participants are primarily focused on seeking and providing assistance with the integration process.

Contextual Notes

Participants have not fully resolved the steps required for the substitution, and there may be assumptions regarding the familiarity with integration techniques that are not explicitly stated.

mckallin
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Definite Integral [help] !

hello, can anyone help me how to complete the following definite integral? Thanks!
∫ (x^2)*sqrt(7 x + 9) dx (From 0 to 1)
 
Last edited:
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Try the substitution

[tex]\sqrt{7x+9}=y[/tex]
 
sorry, I still can't figure out it, can you give me some more detail? thanks a lot .
 
If [itex]y= \sqrt{7x+ 9}[/itex], what is dx (in terms of dy and y)? What is x in terms of y? (So you can substitute for that x2.)
 
I got it, thanks for help! ^-^
 

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