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Gravel

## odesolve "array index invalid"

Hi, I am trying to solve  a simple differential equation that uses an excel acceleration vs time as the driving force. I have used linterp to ensure that time values used in the solve can be extracted from the input acceleration versus time data.There also seems to be an issue with too many initial conditions. I would have thought you need 4 but this solve block only seems to need 3?

Any assistance would be appreciated.

Thanks

ross

1 ACCEPTED SOLUTION

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## Re: odesolve "array index invalid"

@remslie wrote:

Hi, I am trying to solve  a simple differential equation that uses an excel acceleration vs time as the driving force. I have used linterp to ensure that time values used in the solve can be extracted from the input acceleration versus time data.There also seems to be an issue with too many initial conditions. I would have thought you need 4 but this solve block only seems to need 3?

Any assistance would be appreciated.

Thanks

ross

I think you have confused the system (x) with the base (y) at times!  Here's my modification:

Alan

2 REPLIES 2
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## Re: odesolve "array index invalid"

@remslie wrote:

Hi, I am trying to solve  a simple differential equation that uses an excel acceleration vs time as the driving force. I have used linterp to ensure that time values used in the solve can be extracted from the input acceleration versus time data.There also seems to be an issue with too many initial conditions. I would have thought you need 4 but this solve block only seems to need 3?

Any assistance would be appreciated.

Thanks

ross

I think you have confused the system (x) with the base (y) at times!  Here's my modification:

Alan

## Re: odesolve "array index invalid"

Alan,

Many thanks once again for your prompt response and dedication to the Mathcad cause.

Best regards,

Ross