求救!!! 若a為200到500之間的整數則使跟號6a為整數的a值有哪些? p.s.要算是?
回答 (1)
2016-08-12 7:52 am
Sol
Set x=√(6a)
x^2=6a
6｜x^2
6｜x
x=6p
36p^2=6a
a=6p^2
200<a<500
200<6p^2<500
33.33<p^2<83.34
36<=p^2<=81
6<=p<=9
(1) p=6 =>a=216
(2) p=7 =>a=294
(3) p=8 =>a=384
(4) p=9 =>a=486
Set x=√(6a)
x^2=6a
6｜x^2
6｜x
x=6p
36p^2=6a
a=6p^2
200<a<500
200<6p^2<500
33.33<p^2<83.34
36<=p^2<=81
6<=p<=9
(1) p=6 =>a=216
(2) p=7 =>a=294
(3) p=8 =>a=384
(4) p=9 =>a=486
收錄日期: 2021-04-30 21:44:58
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