2010-7-12 11:36 AM
小檸
[linGxl2M0N]♥問功課:(
(x-y)(y-z)(z-x)=xyz-x²-y²-z²
問♥要條式(點計)同埋系咪恆等式``
thz;+20yk
2010-7-12 12:05 PM
XDD
[quote][b]原帖由 [i]小檸[/i] 於 2010-7-12 11:36 AM 發表。 [/b][url=http://forum.eyankit.com/viewthread.php?tid=55151&page=1#pid575707][img]http://forum.eyankit.com/images/common/back.gif[/img][/url]
(x-y)(y-z)(z-x)=xyz-x2-y2-z2
問♥要條式(點計)同埋系咪恆等式``
thz;+20yk [/quote]
介唔介意打晒成條問題出黎@@?
2010-7-12 12:18 PM
小檸
[quote][b]原帖由 [i]XDD[/i] 於 2010-7-12 12:05 發表。 [/b][url=http://forum.eyankit.com/viewthread.php?tid=55151&page=1#pid575727][img]http://forum.eyankit.com/images/common/back.gif[/img][/url]
介唔介意打晒成條問題出黎@@? [/quote]
判斷下列各式是否恆等式.
(x-y)(y-z)(z-x)=xyz-x²-y²-z²
2010-7-12 12:27 PM
XDD
[quote][b]原帖由 [i]小檸[/i] 於 2010-7-12 12:18 PM 發表。 [/b][url=http://forum.eyankit.com/viewthread.php?tid=55151&page=1#pid575738][img]http://forum.eyankit.com/images/common/back.gif[/img][/url]
判斷下列各式是否恆等式.
(x-y)(y-z)(z-x)=xyz-x2-y2-z2 [/quote]
你expand左左面睇下係咪相等咪得囉@@?
2010-7-12 12:46 PM
小檸
[quote][b]原帖由 [i]XDD[/i] 於 2010-7-12 12:27 發表。 [/b][url=http://forum.eyankit.com/viewthread.php?tid=55151&page=1#pid575742][img]http://forum.eyankit.com/images/common/back.gif[/img][/url]
你expand左左面睇下係咪相等咪得囉@@? [/quote]
吾識ex -v-
2010-7-12 04:28 PM
XDD
[quote][b]原帖由 [i]小檸[/i] 於 2010-7-12 12:46 PM 發表。 [/b][url=http://forum.eyankit.com/viewthread.php?tid=55151&page=1#pid575754][img]http://forum.eyankit.com/images/common/back.gif[/img][/url]
吾識ex -v- [/quote]
= =
(x-y)(y-z)(z-x)
(xy - y^2 - xz + zy)(z-x)
(xyz - zy^2 - xz^2 + yz^2 - yx^2 + xy^2 + zx^2 - xyz)
(- zy^2 - xz^2 + yz^2 - yx^2 + xy^2 + zx^2)