Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    Im stuck with this differentiation how do you differentiate

    y=4^x

    Im also having trouble with a decay question (p221 q4 edexcel)

    Ѳ=Ae^-kt

    Where Ѳ is the excess of temperature of the cooling body over its surroundings at time t. For a given liquid, k=1/4, Ѳ is measured in degrees C and t is measured in minutes. The surrounding temp is 20 and at t=0 the temp of the liquid is 60

    a)Find A

    Could somebody help me decipher the question, and maybe write the equation with the known information i know how to do the rest im just not sure what the information ive been given corresponds to!
    Offline

    0
    ReputationRep:
    y=4^x=exp(x(log4))

    then use the chain rule and you're done for that bit
    Offline

    0
    ReputationRep:
    Im stuck with this differentiation how do you differentiate

    y=4^x

    differential of e^x = e^x
    differential of e^f(x) = e^f(x) times the differntial of f(x)
    Offline

    0
    ReputationRep:
    (Original post by sexuali)
    Im stuck with this differentiation how do you differentiate

    y=4^x

    differential of e^x = e^x
    differential of e^f(x) = e^f(x) times the differntial of f(x)
    4 = e^(ln(4))

    So y = e^(ln(4))^x = e^(ln(4)x)
    dy/dx = ln(4)e^(ln(4)x) = 4ln4 e^x
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: January 28, 2010

University open days

  1. University of Bradford
    University-wide Postgraduate
    Wed, 25 Jul '18
  2. University of Buckingham
    Psychology Taster Tutorial Undergraduate
    Wed, 25 Jul '18
  3. Bournemouth University
    Clearing Campus Visit Undergraduate
    Wed, 1 Aug '18
Poll
How are you feeling in the run-up to Results Day 2018?
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

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.