先看碳在葡萄糖中的含量,
72/180
所以溶质的质量分数为20%*(180/72)=50%
由m=1/6t²-11/6t+6得6m=t²-11t+36①
由6/√﹙36-12m)=(11-t)/(6-m)得36-6m=(11-t)√﹙36-12m)②
①代入②得36-﹙t²-11t+36﹚=(11-t)√[36-2﹙t²-11t+36﹚]
﹣t(t-11)=﹣(t-11)√[-2﹙t²-11t+18﹚]
﹣t(t-11)+(t-11)√[-2﹙t²-11t+18﹚]=0
﹣(t-11)﹛t-√[-2﹙t²-11t+18﹚]﹜=0
﹣(t-11)=0或t-√[-2﹙t²-11t+18﹚]=0
对于t-√[-2﹙t²-11t+18﹚]=0即√[-2﹙t²-11t+18﹚]=t(2≦t≦9)
-2﹙t²-11t+18﹚=t²即-2t²+22t-36=t²
3t²-22t+36=0
Δ=﹙﹣22﹚²-4×3×36=52>0
t=﹙22±√52﹚/6=﹙11±√13)/3(2≦t≦9)
综上t=11,﹙11+√13)/3,﹙11-√13)/3
完型:8上p118 p138 p28 p90 8下p47 p82
阅读:8下p12 p28 p122 p4