Under which operation is the set of positive real numbers not closed?
(1) addition
(2) subtraction
(3) multiplication
(4) division
2007-12-10 11:24:15 · 4 answers · asked by ☮ 5 in Science & Mathematics ➔ Mathematics
Thank You! :o)
2007-12-10 11:37:11 · update #1
2 subtraction
for example 5 - 7 = -2
5 is positive and 7 is positive but the result is negative - which is not a member of the set of positive real numbers
2007-12-10 11:32:40 · answer #1 · answered by Anonymous · 1⤊ 0⤋
Because you can subtract one positive number from another and get a negative number. e.g. if 5 is in the set and 7 is also in the set then for a closed set 5 minus 7 would have to be in the set (i.e. be a positive real number). 5 minus 7 is -2 which is negative and not in the set of positive real numbers. Hence the original set is not closed under subtraction.
2016-04-08 07:00:36 · answer #2 · answered by Anonymous · 0⤊ 0⤋
subtraction.
2-3=-1
-1 is not positive real but 2 and 3 both are.
2007-12-10 11:27:32 · answer #3 · answered by Anonymous · 1⤊ 0⤋
2) subtraction
2007-12-10 11:32:16 · answer #4 · answered by santmann2002 7 · 1⤊ 0⤋