2
sigma (1, 1, (function x -> x)) 
TA_Result 1
2
sigma (1, 10, (function x -> x)) 
TA_Result 55
2
sigma (-50, 50, (function x -> x * x)) 
TA_Result 85850
2
sigma (10, 2, (function x -> 10)) 
TA_Result 0
2
sigma (0, 0, (function x -> 2 * x)) 
TA_Result 0