如图,平行六面体ABCD-A'B'C'D'中,AB=5,AD=3,AA'=7,∠BAD=60°∠BAA'=∠DAA'=45°,求AC'的长具体
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如图,平行六面体ABCD-A'B'C'D'中,AB=5,AD=3,AA'=7,∠BAD=60°∠BAA'=∠DAA'=45°,求AC'的长具体
如图,平行六面体ABCD-A'B'C'D'中,AB=5,AD=3,AA'=7,∠BAD=60°∠BAA'=∠DAA'=45°,求AC'的长
具体
如图,平行六面体ABCD-A'B'C'D'中,AB=5,AD=3,AA'=7,∠BAD=60°∠BAA'=∠DAA'=45°,求AC'的长具体
这儿有类似的题
向量AC'=向量AB+向量AD+向量AA'
=>
AC'^2 = (向量AB+向量AD+向量AA')^2
=
AB^2 + AD^2 + AA'^2 + 2(向量AB*向量AD+向量AA'*向量AB+向量AD*向量AA')
=
AB^2 + AD^2 + AA'^2 + 2AB*ADcos60+2AA'*ABcos45+2AD*AA'cos45<...
全部展开
向量AC'=向量AB+向量AD+向量AA'
=>
AC'^2 = (向量AB+向量AD+向量AA')^2
=
AB^2 + AD^2 + AA'^2 + 2(向量AB*向量AD+向量AA'*向量AB+向量AD*向量AA')
=
AB^2 + AD^2 + AA'^2 + 2AB*ADcos60+2AA'*ABcos45+2AD*AA'cos45
=
25+9+49+15+35√2+21√2
=
98+56√2
=>
AC' = √(98+56√2)
收起
向量AC'=向量AB+向量AD+向量AA'
=>
AC'^2 = (向量AB+向量AD+向量AA')^2
=
AB^2 + AD^2 + AA'^2 + 2(向量AB*向量AD+向量AA'*向量AB+向量AD*向量AA')
=
AB^2 + AD^2 + AA'^2 + 2AB*ADcos60+2AA'*ABcos60+2AD*AA'cos60
=
16+9+25+2*4*3/2+2*5*4/2+2*3*5/2
=
97
=>
向量AC'=向量AB+向量AD+向量AA'
=>
AC'^2 = (向量AB+向量AD+向量AA')^2
=
AB^2 + AD^2 + AA'^2 + 2(向量AB*向量AD+向量AA'*向量AB+向量AD*向量AA')
=
AB^2 + AD^2 + AA'^2 + 2AB*ADcos60+2AA'*ABcos45+2AD*AA'cos45<...
全部展开
向量AC'=向量AB+向量AD+向量AA'
=>
AC'^2 = (向量AB+向量AD+向量AA')^2
=
AB^2 + AD^2 + AA'^2 + 2(向量AB*向量AD+向量AA'*向量AB+向量AD*向量AA')
=
AB^2 + AD^2 + AA'^2 + 2AB*ADcos60+2AA'*ABcos45+2AD*AA'cos45
=
25+9+49+15+35√2+21√2
=
98+56√2
=>
AC' = √(98+56√2) 请善用搜索
收起