# Second Order DE helpWatch

#1
Hi
I would like some help on the question below please

Ae^3x + Bxe^3x = 0 is my first thought and then evaluating and matching the differentiated terms of e^3x
I have hit a blank though and this is prior to the PI being introduced which has thrown me further.

Any help would be appreciated.
Thanks

0
7 years ago
#2
(Original post by robertbrooks)
Hi
I would like some help on the question below please

Ae^3x + Bxe^3x = 0 is my first thought and then evaluating and matching the differentiated terms of e^3x
I have hit a blank though and this is prior to the PI being introduced which has thrown me further.

Any help would be appreciated.
Thanks

Since you are told that satisfies that equation, just substitute in and solve, the answer drops out very quickly.
0
#3
Thanks mate
I have had a gone since posting and realised I should have:
Differentiated once and then again and fed that in for each.
Appreciated that e^x can never = 0 so the other parts would and then solved

I assume thats the most efficient way to show it right?

Thanks
Rob
0
7 years ago
#4
(Original post by robertbrooks)
Thanks mate
I have had a gone since posting and realised I should have:
Differentiated once and then again and fed that in for each.
Appreciated that e^x can never = 0 so the other parts would and then solved

I assume thats the most efficient way to show it right?

Thanks
Rob
I reckon so.
1
#5
Thanks for you help.
Rob
0
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