Problems on these two questions

[su29090]

I all of the other problems but I have issues with these:

1.Given a positive integer  n , assign True to  is_prime if  n has no factors other than  1 and itself. (Remember,  m is a factor of  n if  m divides  n evenly.) 

2.An  arithmetic progression is a sequence of numbers in which the distance (or difference) between any two successive numbers if the same. This in the sequence  1, 3, 5, 7, ... , the distance is 2 while in the sequence  6, 12, 18, 24, ... , the distance is 6. 

 Given the positive integer  distance and the positive integer  n , associate the variable  sum with the sum of the elements of the arithmetic progression from  1 to  n with distance  distance . For example, if  distance is 2 and  n is  10 , then  sum would be associated with  26 because  1+3+5+7+9 = 25 . 

Thanks in advance.