Turn on thread page Beta
    • Thread Starter
    Offline

    13
    ReputationRep:
    Name:  IMG_20170122_163920.jpg
Views: 52
Size:  506.0 KB
    Can someone pls help me with question 10 (last one) part B! I've been stuck on it for like 2 hours having no clue what to do ..
    I opened solution banks it started from the gradient of the tangent being 1/q... How does it know???
    • Community Assistant
    Offline

    20
    ReputationRep:
    Community Assistant
    (Original post by pondsteps)
    Name:  IMG_20170122_163920.jpg
Views: 52
Size:  506.0 KB
    Can someone pls help me with question 10 (last one) part B! I've been stuck on it for like 2 hours having no clue what to do ..
    I opened solution banks it started from the gradient of the tangent being 1/q... How does it know???
    Using the chain rule,  \displaystyle \frac{d}{dx}(ln(3x)) = \frac{1}{x}
    From this can find the gradient of the normal, thus the equation of the normal and substitute x=q.
    Offline

    15
    ReputationRep:
    (Original post by NotNotBatman)
    Using the chain rule,  \displaystyle \frac{d}{dx}(ln(3x)) = \frac{1}{x}
    From this can find the gradient of the normal, thus the equation of the normal and substitute x=q.
    Doesnt ln(3x) differentiate to give 3/3x ?
    Oh never mind, that simplifies to 1/x
    school boy error
    • Community Assistant
    Offline

    20
    ReputationRep:
    Community Assistant
    (Original post by bobwibbles)
    Doesnt ln(3x) differentiate to give 3/3x ?
    Yes, which can be simplified to 1/x
    • Thread Starter
    Offline

    13
    ReputationRep:
    Oh I think I got that thank u .. I found a similar question now (also part b) but also didn't known how to solve it 😭
    Name:  IMG_20170122_163928.jpg
Views: 53
Size:  501.5 KB
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 22, 2017

University open days

  • University of Bradford
    All faculties Undergraduate
    Wed, 21 Nov '18
  • Buckinghamshire New University
    All Faculties Postgraduate
    Wed, 21 Nov '18
  • Heriot-Watt University
    All Schools Postgraduate
    Wed, 21 Nov '18
Poll
Black Friday: Yay or Nay?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Equations

Best calculators for A level Maths

Tips on which model to get

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.