# Using substitution to find the exact value of the area issues[Integration]Watch

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#1
The question: https://media.discordapp.net/attachm...289&height=513

For the area I got 2.5774 and I'm not sure if that's correct.

Also for the last question, I'm not sure as to how I can use substitution to integrate it like is that even possible?
0
1 month ago
#2

Show the working, pls, for the substitution processes you've done so far.
It works quite easily, by substitution.
(Original post by OJ Emporium)
The question: https://media.discordapp.net/attachm...289&height=513

For the area I got 2.5774 and I'm not sure if that's correct.

Also for the last question, I'm not sure as to how I can use substitution to integrate it like is that even possible?
0
#3
(Original post by begbie68)

Show the working, pls, for the substitution processes you've done so far.
It works quite easily, by substitution.
What I did:
https://cdn.discordapp.com/attachmen...1901507530.jpg
Last edited by OJ Emporium; 1 month ago
0
1 month ago
#4
You've got du/dx wrong.

Which means you get the wrong function before you integrate.

try again?

or think about implicit diff of u^2 = x.

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#5
(Original post by begbie68)
You've got du/dx wrong.

Which means you get the wrong function before you integrate.

try again?

or think about implicit diff of u^2 = x.
Yeah no im completely confused here lol
0
1 month ago
#6
differentiate 'root(x)'

what do you get?
(Original post by OJ Emporium)
Yeah no im completely confused here lol
0
1 month ago
#7
why are you confused?

u = root x
you did du/dx and you got it wrong.

Try again.

Which bit is confusing?
(Original post by OJ Emporium)
Yeah no im completely confused here lol
0
#8
i derived that and ended up getting du/dx = 1/2x and rearranged that to get 2du/x = dx

(Original post by begbie68)
why are you confused?

u = root x
you did du/dx and you got it wrong.

Try again.

Which bit is confusing?
0
1 month ago
#9
Cool.

I'd usually leave it as 2udu = dx

Then, change limits
and sub for x, root x in the function

Simplify the function (if needed)

Integrate

So the limits thing and subtract, then simplify if needed.

Should be straight forward
(Original post by OJ Emporium)
i derived that and ended up getting du/dx = 1/2x and rearranged that to get 2du/x = dx
0
#10
(Original post by begbie68)
Cool.

I'd usually leave it as 2udu = dx

Then, change limits
and sub for x, root x in the function

Simplify the function (if needed)

Integrate

So the limits thing and subtract, then simplify if needed.

Should be straight forward
Yeah i noticed i made a minor mistake from this, thank you man
0
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