解:∵A∩B=B??? ∴A包含B?? ∵A={x│x2+3x+2=0}={1,2}? ∴B=空集、{1}、{2}、{1,2}
????當(dāng)B=空集時(shí)????Δ=b2-4ac=m2-8<0????-2×根號(hào)2<m<2×根號(hào)2?
????當(dāng)B={1}時(shí)????Δ=b2-4ac=m2-8=0且12-1×m+2=0????m∈空集
????當(dāng)B={2}時(shí)????Δ=b2-4ac=m2-8=0且22-2×m+2=0????m∈空集
????當(dāng)B={1,2}時(shí)??? Δ=b2-4ac=m2-8>0且12-1×m+2=0且22-2×m+2=0????m∈空集
????綜上所述????-2×根號(hào)2<m<2×根號(hào)2?
高一 數(shù)學(xué) 必修一
y2=1-x2
m-n=loga(1+x)-loga(1/1-x)=loga(1-x2)=loga(y2)=2loga y
loga y=(m-n)/2
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2log a(M-2N)=loga M+loga N=loga MN
(M-2N)2=MN
M2-4MN+4N2=MN
M2-5MN+4N2=0
(M-4N)(M-N)=0
由于M>0,N>0,M>2N
M=4N,M/N=4
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