Need these done on matlab

6. 7, 8. (10%) Develop a function to calculate the factorial n! (e.g., 0|-1,1|-1, 2|-23)-6,4|- (10%) Develop a function to accept an arbitrary vector provided by the user and by using a loop compute the sum of its elements. (10%) Develop a function to accept an arbitrary vector provided by the user and by using a loop multiply each element of this vector by a number entered by the user