Shaanv
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#1
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Hi guys can anyone take a look at my working out for question 3 part a. I think the solution bank has forgotten to convert the limits for x terms to u terms.

Image
Image
Image

Thanks in advance.

Edit: my initial link had a banned word in the random string of letters from imgur😂
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RDKGames
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(Original post by Shaanv)
Edit: my initial link had a banned word in the random string of letters from imgur😂
Both you and the scheme are incorrect.

x^2+2x+5=(x+1)^2+4

So, \displaystyle \int_{1}^3 \frac{dx}{\sqrt{x^2+2x+5}} = \int_1^3 \frac{dx}{\sqrt{(x+1)^2+4}}

Let u=x+1

The domain is shifted 1 unit along to:

\displaystyle \int_2^4 \frac{du}{\sqrt{u^2+4}}
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Notnek
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(Original post by Shaanv)
Hi guys can anyone take a look at my working out for question 3 part a. I think the solution bank has forgotten to convert the limits for x terms to u terms.

Image
Image
Image

Thanks in advance.

Edit: my initial link had a banned word in the random string of letters from imgur😂
There are typos somewhere. The solution working has original limits 0 and 1. Check the actual question from the textbook.
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NotNotBatman
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(Original post by Shaanv)
Hi guys can anyone take a look at my working out for question 3 part a. I think the solution bank has forgotten to convert the limits for x terms to u terms.

Image
Image
Image

Thanks in advance.

Edit: my initial link had a banned word in the random string of letters from imgur😂
The limits say 1 and 3 in the question?
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Shaanv
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Report Thread starter 3 years ago
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(Original post by RDKGames)
Both you and the scheme are incorrect.

x^2 2x 5=(x 1)^2 4

So, \displaystyle \int_{1}^3 \frac{dx}{\sqrt{x^2 2x 5}} = \int_1^3 \frac{dx}{\sqrt{(x 1)^2 4}}

Let u=x 1

The domain is shifted 1 unit along to:

\displaystyle \int_2^4 \frac{du}{\sqrt{u^2 4}}
(Original post by Notnek)
There are typos somewhere. The solution working has original limits 0 and 1. Check the actual question from the textbook.
(Original post by NotNotBatman)
The limits say 1 and 3 in the question?
The limits in solution bank are different to the textbook, the textbook has limits of 2 and 1. However the solution banks working out for part a changes the limits to 1 and 0.

The plot thickens😂.

Thanks guys.
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