How to code difference quotients in matlab?

I have a vector U and I want to take its difference quotient at a time instance j i.e. I want to find dU as shown below. How can it be done?

Thank you guys in advance!

Answer 1

[Jonas]

elementwise differences of consecutive elements can be calculated using diff() command

[ekagra gupta]

I tried but actually I need ratio of variance of these difference quotients. that is returning NaN values at some points.

[Image Analyst]

U = randi(9, 1, 10)

U = 1×10

2 2 5 8 2 7 8 9 5 1

% Compute difference
du = diff(U)

du = 1×9

0 3 3 -6 5 1 1 -4 -4

% Compute variance
varU = var(du)

varU = 14.1111

Not sure what you mean by ratio. A ratio is a fraction of something divided by something. What are you ratioing? The ratio of a single number -- the variance -- doesn't make sense.