Confusion on a differentiation question Watch

coconut64
Badges: 16
Rep:
?
#1
Report Thread starter 2 years ago
#1
Name:  14786027862192011439746.jpg
Views: 58
Size:  358.4 KB for question 8, I can't seem to prove it. Attachment 593372593374

Thanks
Attached files
0
reply
maruchan
Badges: 11
Rep:
?
#2
Report 2 years ago
#2
(Original post by coconut64)
Name:  14786027862192011439746.jpg
Views: 58
Size:  358.4 KB for question 8, I can't seem to prove it. Attachment 593372593374

Thanks
x = sec y

d/dx(x) = d/dy(sec y))

1 = dy/dx sec y tan y

dy /dx = 1 / (sec y tan y)


tan^2 y + 1= sec^2 y
tan y = √(sec^2y - 1)



dy/dx = 1 / [x √(x^2 - 1)]


hope that helps
1
reply
coconut64
Badges: 16
Rep:
?
#3
Report Thread starter 2 years ago
#3
(Original post by maruchan)
x = sec y

d/dx(x) = d/dy(sec y))

1 = dy/dx sec y tan y

dy /dx = 1 / (sec y tan y)


tan^2 y + 1= sec^2 y
tan y = √(sec^2y - 1)



dy/dx = 1 / [x √(x^2 - 1)]


hope that helps
Thanks, that is a very detailed explanation ! however do u know that's implicit differentiation ? I thought it was a normal differentiation with subsitutuion ..
0
reply
ghostwalker
  • Study Helper
Badges: 16
#4
Report 2 years ago
#4
(Original post by coconut64)
for question 8, I can't seem to prove it.
Thanks
Note that you had x=f(y)

What you worked out on the left is dx/dy, NOT dy/dx.

Using dy/dx = 1/(dx/dy) would put you back on the right track.
0
reply
coconut64
Badges: 16
Rep:
?
#5
Report Thread starter 2 years ago
#5
(Original post by ghostwalker)
Note that you had x=f(y)

What you worked out on the left is dx/dy, NOT dy/dx.

Using dy/dx = 1/(dx/dy) would put you back on the right track.
Thanks
0
reply
maruchan
Badges: 11
Rep:
?
#6
Report 2 years ago
#6
(Original post by coconut64)
Thanks, that is a very detailed explanation ! however do u know that's implicit differentiation ? I thought it was a normal differentiation with subsitutuion ..

Yes i just used implicit differentiation because i found it easier to do it that way. As it says x=secy i think it's best to use implicit differentiation
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts

All the exam results help you need

2,272

people online now

225,530

students helped last year

University open days

  • Sheffield Hallam University
    Clearing open day Undergraduate
    Tue, 20 Aug '19
  • Bournemouth University
    Clearing Open Day Undergraduate
    Wed, 21 Aug '19
  • University of Dundee
    Undergraduate Open Day Undergraduate
    Mon, 26 Aug '19

Are you going to self-release into Clearing?

Yes I've pressed the button (96)
18.82%
No I'm happy with my uni offer (324)
63.53%
Not yet but I am planning to (24)
4.71%
Not yet but I might (66)
12.94%

Watched Threads

View All