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40 x 1/2t + 50 x 1/2t=S (1/2S-40)/40 + (1/2S+40)/55 + 0.5=t

分类: 作业答案 • 2022-07-01 13:48:21
问题描述：

40 x 1/2t + 50 x 1/2t=S (1/2S-40)/40 + (1/2S+40)/55 + 0.5=t

答

40 x 1/2t + 50 x 1/2t=S (1/2S-40)/40 + (1/2S+40)/55 + 0.5=t
45/t^2=S (1/2S-40)/40 + (1/2S+40)/55 + 0.5
=[11S(1/2S-40)+8(1/2S+40)+0.5*440]/440
=[5.5-440S+4/S+320+220]/440
45/t^2=[4/S-440S+545.5]/440
45*440/t^2=4/S-440S+545.5
t^2=19800/[4/S-440S+545.5]

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