$版本(*“14.0.0适用于Mac OS X ARM(64位)(2023年12月13日)”*)清除[“全局`*”];f1[x_]:=1.333+28.846/x;f2[x_]:=1.333+28.846/(115/平方[3]);plotData={{53.1,2.026},{54.8,1.679},}56.4,1.582},[58.1,1.597}, {59.8, 2.013}, {61.4, 1.993}, {63.1, 1.952}, {64.7, 1.867}, {66.4, 1.819}, {68.1, 1.862}, {69.7, 1.733}, {71.4, 1.692}, {73, 1.726}, {74.7, 1.697}, {76.4, 1.654}, {78, 1.672}, {79.7, 1.596}};dataPointCross={115/Sqrt[3],f1[115/Sqrt[3]]};plt=绘图[{f1[x],f2[x]},{x,0,90},尾声->{点@plotData,红色,点大小[0.015],点@dataPointCross},绘图范围->{{45,90},{1,3}},PlotStyle->{蓝色,方向[黑色,虚线]},PlotTheme->“科学”,绘图图例->{放置[“表达式”,{.8,.8}],SwatchLegend[{HatchFilling[Pi/4,1,5] ,{图案填充[-Pi/4,4,12],蓝色}},{“\!\(\*SubscriptBox[\(S\),\(neg\)]\)”,“\!\(\*订阅框[\(S\),\(pos\)]\)”},图例标记大小->30]},图像大小->大,标签样式->指令[Black,FontSize->14,FontFamily->“Times New Roman”],FrameLabel->{Style[“U”,粗体,黑色,FontSize->14],样式[“K”,粗体,黑色,字体大小->14]},填充->{{1->{{2},{{HatchFilling[-Pi/4,4,12],蓝色},图案填充[Pi/4,1,5]}}}];
计算面积的步骤
areaSneg=积分[f1[x]-f2[x],{x,0.8*115/平方[3],115/平方[3]}](* 0.667599 *)rgnSneg=隐式区域[f2[x]<y<f1[x]&&(0.8*115/Sqrt[3])<x<115/Sqrt[3],{x,y}];积分[1,{x,y}∈rgnSneg](* 0.667599 *)区域[DiscretizeRegion[rgnSneg,MaxCellMeasure->{“Length”->.01}]](* 0.667599 *)
同样,
areaSpos=积分[f2[x]-f1[x],{x,115/Sqrt[3],1.2*115/Sqrt[3]}](* 0.509952 *)rgn位置=隐式区域[f1[x]<y<f2[x]&&115/Sqrt[3]<x<(1.2*115/Sqrt[3]),{x,y}];积分[1,{x,y}∈rgnPos](* 0.509952 *)区域[DiscretizeRegion[rgnPos,MaxCellMeasure->{“Length”->.01}]](* 0.509952 *)
图形化,
显示[plt,区域[Style[rgnSneg,Opacity[0.25,Blue]],区域[样式[rgnPos,不透明度[0.25,红色]]]