求解!!!!!! 急需?
回答 (1)
2017-06-09 12:15 pm
Sol
B－E－C
C－F－D
a=BE，b=CE，c=CF，d=DF
2x=(a+b)d
2y=a(c+d)
2z=bc
x+y+z+k=(a+b)(c+d)
2x+2y+2z+2K=2ac+2ad+2bc+2bd
ad+bd+ac+ad+bc+2k=2ac+2ad+2bc+2bd
2k=ac+bc+bd
2x+2y+2z－2k
=ad+bd+ac+ad+bc－ac－bc－bd
=2ad
(x+y+z)^2－k^2
=(x+y+z+k)(x+y+z－k)
=(a+b)*(c+d)*2ad
=[(a+b)d]*[(c+d)a]
=(2x)*(2y)
=4xy
B－E－C
C－F－D
a=BE，b=CE，c=CF，d=DF
2x=(a+b)d
2y=a(c+d)
2z=bc
x+y+z+k=(a+b)(c+d)
2x+2y+2z+2K=2ac+2ad+2bc+2bd
ad+bd+ac+ad+bc+2k=2ac+2ad+2bc+2bd
2k=ac+bc+bd
2x+2y+2z－2k
=ad+bd+ac+ad+bc－ac－bc－bd
=2ad
(x+y+z)^2－k^2
=(x+y+z+k)(x+y+z－k)
=(a+b)*(c+d)*2ad
=[(a+b)d]*[(c+d)a]
=(2x)*(2y)
=4xy
收錄日期: 2021-04-30 22:20:28
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20170608132138AAp3Wmg