# Climbing Power Equation: how to make a calculation into usable code

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Robert J Hanna on 24 Nov 2020
Commented: Robert J Hanna on 27 Nov 2020
I'm trying to write a specific equation that includes derivation. This specifically:
The data I am looking at is from three cameras focused on a flying bird. after running the position data through some smoothing functions its derived to get velocity and acceleration.
So I'm working with the velocities in the X,Y, and Z directions in an excel file (aDdatafilt1).
Heres what I have so far but I don't think Im using diff() correctly:
%GENERATE CLIMB POWER FOR BIRD "A"
t=[1/60] ; %fps of cams = 60
XYVel=sqrt(XVel.^2+YVel.^2);
Pkmt=(.5.*abs(XYVel).^2+(9.8)*(ZPos));
Pkm = diff(Pkmt,t)
Thanks.

Rohit Pappu on 27 Nov 2020
To calculate the first derivative of a particular vector X, the syntax is diff(X,1)
For the above equation,
Pkm = diff(Pkmt,1)/t
is equivalent to
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Robert J Hanna on 27 Nov 2020
Thank you! that worked

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