MATLAB: How to calculate the length of a vector, if x and y of a vector are both in formula form

dsiplacementMATLABvelocity

Here is the requirement for coding, first line of coding is the range of x and y, vecyx is dL/dx, vecy is dL/dy. Those are provided by the requriement.
Then following the requirement's description. I used V=[ ] ; length(v) to calculate the length, but it just come up one result. But according to the description, the reulst should be an array. So how do i code it? Many thanks!!!!!!
for ask.png
[x,y]=meshgrid(0:0.01:50, 0:0.01:30);
vecx=((2*x-30)/(2*sqrt(850-30*x-50*y+x.^2+y.^2))+((2*x-20)/(2*sqrt(125-20*x-10*y+x.^2+y.^2)))+((2*x-80)/(2*sqrt(1700-80*x-20*y+x.^2+y.^2))));
vecy=((2*y-50)/(2*sqrt(850-30*x-50*y+x.^2+y.^2))+((2*y-10)/(2*sqrt(125-20*x-10*y+x.^2+y.^2)))+((2*y-20)/(2*sqrt(1700-80*x-20*y+x.^2+y.^2))));
V=[vecx vecy];
L=length(V);

Best Answer

The v is a vector, and the question wants the length of v but not in elements, but in real world units. For example if my vx was [1,2] and my vy was [1,2] then my length in elements would be 2 because length(vx) = 2, however my length of my x is sqrt(2) - the length of the vector going from (1,1) to (2,2). So what you need to do to compute the length along your v vector is summing along all the delta v from one element to the next. See if you can use diff() and sqrt() and sum() to do that.
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