You are Here: Home >< Maths

Differentiation Problems! watch

1. 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!
2. y=4^x=exp(x(log4))

then use the chain rule and you're done for that bit
3. 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. (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

Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: January 28, 2010
Today on TSR

Thought he was 19... really he's 14

University open days

Wed, 25 Jul '18
2. University of Buckingham
Wed, 25 Jul '18
3. Bournemouth University
Wed, 1 Aug '18
Poll
Useful resources

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

How to use LaTex

Writing equations the easy way

Study habits of A* students

Top tips from students who have already aced their exams

Chat with other maths applicants