# Finding Max Rate of Change with Exceptions

• Hi guys,

I have come across a tricky problem I need to solve in Excel. Basically I'm conducting experiments and the chosen output is temperatures histories (Temperature on the y axis, and time on the x axis), which is shown in the photo below.

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However the problem is, due to the experiments nature sometimes there are sharp increases temperatures below 100-150 C (Shown in the black box in the photo below) and prevent me from accurately calculating the desired max rate of change (Shown in the blue box). So my question is, does anywhere no an effective way to calculate the max rate of change but limit it too only calculate the max rate of change above 100-150C.
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Background:

Just for some background, I have already know how to calculate the max rate of change: C/s, and I would rather not manually (Only start the formula above 100 C) as I have over 150 experiments to analyse. Also the reason I am trying to calculate it, is to calculate the time difference between each max rate of change to calculate the velocity of propagation; just in case you wanted to know

Any help would be really appreciated And if you have any questions regarding the situation, feel free to ask. Thanks.

Harry

## Images

• Re: Finding Max Rate of Change with Exceptions

Harry - I suggest you post a workbook with a small sample of data.

• Re: Finding Max Rate of Change with Exceptions

Curve fit with LINEST() and take the derivative.
Attach *.xlsx, not *.jpg
or upload big file to any file sharing site and post link.

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