14(a^2+b^2+c^2)=(a+2b+3c),求证a∶b∶c=1∶2∶3.在△ABC中,AD⊥BC于D,AB=9,AC=6,M是AD上任意一点,则MB^2-MC^2=( ).已知:M、N为等腰直角三角形ABC斜边AB上两点,且∠MCN=45°,求证:AM^2+BN^2=MN^2.要思路
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![14(a^2+b^2+c^2)=(a+2b+3c),求证a∶b∶c=1∶2∶3.在△ABC中,AD⊥BC于D,AB=9,AC=6,M是AD上任意一点,则MB^2-MC^2=( ).已知:M、N为等腰直角三角形ABC斜边AB上两点,且∠MCN=45°,求证:AM^2+BN^2=MN^2.要思路](/uploads/image/z/2581112-56-2.jpg?t=14%28a%5E2%2Bb%5E2%2Bc%5E2%29%3D%28a%2B2b%2B3c%29%2C%E6%B1%82%E8%AF%81a%E2%88%B6b%E2%88%B6c%3D1%E2%88%B62%E2%88%B63.%E5%9C%A8%E2%96%B3ABC%E4%B8%AD%2CAD%E2%8A%A5BC%E4%BA%8ED%2CAB%3D9%2CAC%3D6%2CM%E6%98%AFAD%E4%B8%8A%E4%BB%BB%E6%84%8F%E4%B8%80%E7%82%B9%2C%E5%88%99MB%5E2-MC%5E2%3D%EF%BC%88+%EF%BC%89.%E5%B7%B2%E7%9F%A5%EF%BC%9AM%E3%80%81N%E4%B8%BA%E7%AD%89%E8%85%B0%E7%9B%B4%E8%A7%92%E4%B8%89%E8%A7%92%E5%BD%A2ABC%E6%96%9C%E8%BE%B9AB%E4%B8%8A%E4%B8%A4%E7%82%B9%2C%E4%B8%94%E2%88%A0MCN%EF%BC%9D45%C2%B0%2C%E6%B1%82%E8%AF%81%EF%BC%9AAM%EF%BC%BE2%EF%BC%8BBN%EF%BC%BE2%EF%BC%9DMN%EF%BC%BE2.%E8%A6%81%E6%80%9D%E8%B7%AF)
14(a^2+b^2+c^2)=(a+2b+3c),求证a∶b∶c=1∶2∶3.在△ABC中,AD⊥BC于D,AB=9,AC=6,M是AD上任意一点,则MB^2-MC^2=( ).已知:M、N为等腰直角三角形ABC斜边AB上两点,且∠MCN=45°,求证:AM^2+BN^2=MN^2.要思路
14(a^2+b^2+c^2)=(a+2b+3c),求证a∶b∶c=1∶2∶3.
在△ABC中,AD⊥BC于D,AB=9,AC=6,M是AD上任意一点,则MB^2-MC^2=( ).
已知:M、N为等腰直角三角形ABC斜边AB上两点,且∠MCN=45°,求证:AM^2+BN^2=MN^2.要思路或过程
14(a^2+b^2+c^2)=(a+2b+3c),求证a∶b∶c=1∶2∶3.在△ABC中,AD⊥BC于D,AB=9,AC=6,M是AD上任意一点,则MB^2-MC^2=( ).已知:M、N为等腰直角三角形ABC斜边AB上两点,且∠MCN=45°,求证:AM^2+BN^2=MN^2.要思路
先说第2题 主线是勾股定理 MB^2-MC^2=MD^2+BD^2-(DC^2+DM^2)=BD^2-DC^2=BA^2-AD^2-(AC^2-AD^2)=BA^2-AC^2=9^2-6^2=45 另外两道自己加油吧 嘿嘿
已知a-b-c=2,则-a(a-b-c)+b(a-b-c)+c(a-b-c)
3a-c=4a+2b-c=a+b+c a:b:c
[b/(a-b+c)]+[(2a+c)/(b-a-c)]-[(b-c)/(b-a-c)]
b/a-b+c+2a+c/b-a-c-b-c/b-c-a
a/b/c是不相等实数,求证:(b-c)/(a-b)(a-c)+(c-a)/(b-c)(b-a)+(a-b)/(c-a)(c-b)=2/(a-b)+2/(b-c)+2(c-a)
行列式证明|b+c c+a a+b| | a b c||a+b b+c c+a| = 2 |c a b||c+a a+b b+c| | b c a|
设a,b,c为整数,且a*a+b*b+c*c-2a+4b-6c+14=0,求a,b,c
化简a(a+b)(a+c)/(a-b)(a-c) +2b^2(c-a)/(b-c)(b-a) +2c^2(a+b)/(c-a)(c-b)
化简a(a+b)(a+c)/(a-b)(a-c) +2b^2(c-a)/(b-c)(b-a) +2c^2(a+b)/(c-a)(c-b)
已知:(a-b)(b-c)(c-a)/(a+b)(b+c)(c+a)=5/132,求a/(a+b)+b/(b+c)+c/(c+a)的值!(请尽快,我有急用,a/(a+b)+b/(b+c)+c/(c+a)=1/2[(a-b)/(a+b)+(b-c)/(b+c)+(c-a)/(c+a)]+3/2 (a-b)/(a+b)+(b-c)/(b+c)+(c-a)/(c+a) 没有错吧...
a=3b,c=2a*3,a+b+c*a+b-c=?
求证(a+b)/2c+(b+c)/2a+(a+c)/2b>=2c/(a+b)+2a/(b+c)+2b/(a+c)
为什么[(a+b)^2-c^2)][(a-b)^2-c^2)]=(a+b+c)(a+b-c)(a-b+c)(a-b-c)?
已知a,b,c是正数,求证a^2a*b^2b*c^2c>=a^(b+c)*b^(c+a)*c^(a+b)
如何证明数论题[a,b,c]^2/[a,b][b,c][c,a]=(a,b,c)^2/(a,b)(b,c)(c,a)
若a/b+c=b/c+a=a+c/a+b+2c,则a:b=
(a-b+c/a+b-c)-(a-2b+3c/b-c+a)+(b-2c/c-a-b)
若b/a+b= a+c-b/b+c-a=a+b+c/2a+b+2c,则a∶b∶c=________.