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

OJ Emporium
Badges: 10
Rep:
?
#1
Report Thread starter 1 month ago
#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
reply
begbie68
Badges: 16
Rep:
?
#2
Report 1 month ago
#2
seems reasonable answer to (a) & (b). What about (c)?

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
reply
OJ Emporium
Badges: 10
Rep:
?
#3
Report Thread starter 1 month ago
#3
(Original post by begbie68)
seems reasonable answer to (a) & (b). What about (c)?

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
reply
begbie68
Badges: 16
Rep:
?
#4
Report 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.

0
reply
OJ Emporium
Badges: 10
Rep:
?
#5
Report Thread starter 1 month ago
#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
reply
begbie68
Badges: 16
Rep:
?
#6
Report 1 month ago
#6
differentiate 'root(x)'

what do you get?
(Original post by OJ Emporium)
Yeah no im completely confused here lol
0
reply
begbie68
Badges: 16
Rep:
?
#7
Report 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
reply
OJ Emporium
Badges: 10
Rep:
?
#8
Report Thread starter 1 month ago
#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
reply
begbie68
Badges: 16
Rep:
?
#9
Report 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
reply
OJ Emporium
Badges: 10
Rep:
?
#10
Report Thread starter 1 month ago
#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
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • SOAS University of London
    Postgraduate Open Day Postgraduate
    Wed, 29 May '19
  • University of Exeter
    Undergraduate Open Day - Penryn Campus Undergraduate
    Thu, 30 May '19
  • Cranfield University
    Cranfield Forensic MSc Programme Open Day Postgraduate
    Fri, 31 May '19

How did your AQA A-level Business Paper 1 go?

Loved the paper - Feeling positive (195)
22.65%
The paper was reasonable (394)
45.76%
Not feeling great about that exam... (158)
18.35%
It was TERRIBLE (114)
13.24%

Watched Threads

View All
Latest
My Feed