7. Write and test a function called twice that doubles the value of its input variable (i.e. the statement x= twice(y) should double the value of y).

help me to solve this problem can i use for loop for this problem.?

[Guillaume]

Seriously? Have you even though about what the question is asking? It is such a simple function to write.

How do you manually double the value of a number? How do you write the same in matlab?

If you can't answer that question, then I'd suggest you go back to your course notes or try Getting Started