Solve Initial Value Problem Using Exponential Functions | Step-by-Step Guide"

[-EquinoX-]

Homework Statement

http://img40.imageshack.us/img40/7032/48975587.th.jpg

http://img42.imageshack.us/img42/7264/solve2.jpg

Homework Equations

The Attempt at a Solution

what I get is

m^3e^(mx) + 10m^2e^(mx) + 9me^(mx) = 0
e^(mx) * (m^2 + 10m + 9)
e^(mx) * (m+9)(m+1)
m = -9 and m = -1 in order for this to be 0

 

[lanedance]

is there a question?

also I would outline your initial assumption to help, and as a start look at putting a constant through your DE

 

[-EquinoX-]

yes the question is here:

http://img40.imageshack.us/img40/7032/48975587.jpg

 

[gabbagabbahey]

If m(m+9)(m+1)=0, =m-1 and m=-9 aren't the only possible values of m are they?

 

[-EquinoX-]

yes, but web assign for some reason won't accept that answer

 

[gabbagabbahey]

You have a cubic equation, so there should be 3 roots...you've only listed two of them...

 

[-EquinoX-]

what's the other one? m = 0?

 

[gabbagabbahey]

Yep.