# Exponentials & LogarithmsWatch

Thread starter 10 years ago
#1
I'm trying to solve:

1+e^(2x+1)=3-e^x

I've got as far as:

e.e^(2x)+e^x-2=0

But I can't factorise it. Any help would be appreciated. Thanks x
0
10 years ago
#2
(Original post by OllyThePhilosopher)
I'm trying to solve:

1+e^(2x+1)=3-e^x

I've got as far as:

e.e^(2x)+e^x-2=0

But I can't factorise it. Any help would be appreciated. Thanks x
It might not be easily factorisable - if you can't use the quadratic formula
0
10 years ago
#3
(Original post by nuodai)
By the looks of it you need to take logarithms of both sides:

Spoiler:
Show
1 + e^(2x+1) = 3 - e^x
ln 1 + (2x+1) = ln 3 + x
x = ln 3 - 1

Actually I think I'm wrong here, but yeah.
Very very poor.

Use the quadratic formula. You can't factorise that in a simple way. Especially seeing as you have e as a coefficient.
0
Thread starter 10 years ago
#4
(Original post by nuodai)
Actually I think I'm wrong here, but yeah.
Lol, yeah you can't log like that. Thanks anyway though.
0
10 years ago
#5
I realised how stupid I was after posting, and I couldn't be bothered to delete it. I might do that now actually, sorry!
0
Thread starter 10 years ago
#6
(Original post by aster100)
Very very poor.

Use the quadratic formula. You can't factorise that in a simple way. Especially seeing as you have e as a coefficient.
I think you're right. Thank you
0
10 years ago
#7
Quadratic formula. If that fails... Numerical Methods and find the range of the roots... I doubt that'd happen though. >.>;
0
X

new posts
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

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

### University open days

• Cardiff Metropolitan University
Undergraduate Open Day - Llandaff Campus Undergraduate
Sat, 27 Apr '19
• University of East Anglia
Could you inspire the next generation? Find out more about becoming a Primary teacher with UEA… Postgraduate
Sat, 27 Apr '19
• Anglia Ruskin University
Health, Education, Medicine and Social Care; Arts, Humanities and Social Sciences; Business and Law; Science and Engineering Undergraduate
Sat, 27 Apr '19

### Poll

Join the discussion

#### Have you registered to vote?

Yes! (551)
37.84%
No - but I will (114)
7.83%
No - I don't want to (102)
7.01%
No - I can't vote (<18, not in UK, etc) (689)
47.32%