Problem #$4$: Create a new function file called modify$\_$matrix.m$.$ Then copy and paste the contents of the

create$\_$matrix.m file into this new file, and change the name of the function in the first line to

modify$\_$matrix$($instead of create$\_$matrix$).$

By further modifying this new file, write a function that will output a matrix A obtained by modifying an input

matrix $B$ in the following way:

If an entry in $B$ is greater than or equal to zero then multiply it by $4$

If an entry in $B$ is less than zero then add $4$ to it$.$

Then use this new function to create a matrix A obtained by modifying the following $2828$ matrix $B($which you

can copy and paste directly into Matlab$).$ Then find the determinant of $A$

$81810$;$1-86-405-10-0-2-823-2-9-677-32-777-469-8-575$;$59-9-1019-55-1-89-26-1-1-20$

$3-92-2-27-7-8--6-4-10$

Warning! When Matlab first reads a function from a file, it stores the function in memory and then uses that

stored function instead of reading the file in subsequent calls to the function. Therefore if after calling a function

you then make changes to that file, those changes will not be made when you call the function again unless you

first clear the function from memory using the clear command $($for example, 'clear modify$\_$matrix'$).$