Help to construct vectors

Hi friends,

can anyone help me to construct this vectors:

construct a vector containing numbers starting at 20 and counting backwards by ones to 10

construct a vector containing 15 randomly generated numbers between 1and 2

Answer 1

[Stephen23]

Here is the first solution using the colon operator:

>> 20:-1:10
ans =
  20    19    18    17    16    15    14    13    12    11    10

Learners learn most when they actually try things and learn from experience. Part of that process is learning where to find information, and actually MATLAB has great documentation which you can easily search using your favorite internet search engine. When I searched for "MATLAB random vector", the first links were the documentation that will tell you how to solve your second task.

If your favorite internet search engine is not working, then follow this link:

http://www.mathworks.com/help/matlab/math/create-arrays-of-random-numbers.html

Because these tasks are really very basic you should do these tutorials:

http://www.mathworks.com/help/matlab/getting-started-with-matlab.html

[Mourchid]

thanks a lot for the first answer, for the seconde one i have a problem to generate the random vector for a specific interval, for example between 1 and 2. How can i do that ?

[Guillaume]

On the first page that Stephen linked, the first entry under Related Examples reads: Random Numbers Within a Specific Range. Does that not answer your question?

In your particular case, since rand returns numbers between 0 and 1, just add 1 to the result to make it between 1 and 2.

[Mourchid]

Thank you Guillaume for your answer.