# Math Help - Solving Exponential Equations

1. ## Solving Exponential Equations

Can someone help me solve this equation
$e^x=x+2$

P.S

2. Are you sure that is the correct problem? Just making sure cause i just took a shot at it and i cannot figure it out....

3. Originally Posted by Paymemoney
Can someone help me solve this equation
$e^x=x+2$

P.S
In short, it can't be solved exactly.

You would have to use Numerical methods like the Bisection Method or Newton's Method.

4. Originally Posted by Prove It
In short, it can't be solved exactly.

You would have to use Numerical methods like the Bisection Method or Newton's Method.
I thought this seemed weird to be in the pre-algebra and algebra section cause i am in calculus and solving this was beyond my knowledge

5. yeh just looked at the question it says you need a graphics calculator to solve this one.

6. On a random note, a few years of college will teach you how to use the Lambert W function to solve these equations.
Lambert W function - Wikipedia, the free encyclopedia

These types of questions always pop up on the forum once in a while. I'll give links when I have the time.

7. Here's a link to a similar question that links to another similar question.

http://www.mathhelpforum.com/math-he...nequality.html

8. ## Re: Solving Exponential Equations

Originally Posted by Paymemoney
Can someone help me solve this equation
$e^x=x+2$

P.S
___________-x
1 = (x + 2) e

__
-2___________-x-2
-e__= - (x + 2) e____, where x >= -2

_____________-2
-x-2 = W-1( -e___)

______________-2
x = -2 - W-1( -e___) (x >= -2)

where W-1 is the negative branch of order -1 of Lambert's W function. Go to Lambert W function - Wikipedia, the free encyclopedia to find out how to compute this branch; you can use W-1(x) = ln(-x) - ln(-ln(-x)) or something more complex, depending on the accuracy required

9. ## Re: Solving Exponential Equations

This equation cannot be solved algebraically as it is trancedendal .
you may use graphical methods or numerical ones.
I enclose a graphical one the red line y=x+2 intercepts the blue curve y=e^x at two points...with their coordinates marked in the two figures below.

10. ## Re: Solving Exponential Equations

useless and childish