VPASolve() only one Solution instead of two Solutions

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IlPadrino
IlPadrino 2018-7-5
回答： Star Strider 2018-7-5
Hi guys i have a Problem. I have a Polynom high Degree:
poly = 1/2 == (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - th/200 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600))/14 - (25*((7*th)/25 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2) - 497/100)*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - (7*th)/100 + 509/400))/14 - th/200 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2)/56 + (25*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)^2)/14 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600))/28 - (625*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)*((7*th)/25 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2) - 497/100)^2)/1568 - th/200 - (25*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - (7*th)/100 + 509/400))/14 - th/200 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2)/56 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600))/7 + (625*((7*th)/25 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2) - 497/100)^3)/18816 + th*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - (7*th)/100 + 509/400))/14 - th/200 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2)/56 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600) + (625*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/8 - (7*th)/200 + 509/800))/196 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/784 + (625*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^3)/2352 - (625*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^3)/2352 - (625*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)^3)/294 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 501/5600
if i use vpasolve(poly,th) I get 1 Solution.
ans =18.059378423543239434615372667097
But if i know print this polynom i see clearly 2 Solutions. Where is the other one ?
profile4_2=@(th) -1/2 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - th/200 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600))/14 - (25*((7*th)/25 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2) - 497/100)*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - (7*th)/100 + 509/400))/14 - th/200 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2)/56 + (25*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)^2)/14 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600))/28 - (625*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)*((7*th)/25 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2) - 497/100)^2)/1568 - th/200 - (25*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - (7*th)/100 + 509/400))/14 - th/200 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2)/56 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600))/7 + (625*((7*th)/25 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2) - 497/100)^3)/18816 + th*((25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - (7*th)/100 + 509/400))/14 - th/200 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/56 - (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2)/56 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 613/5600) + (625*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^2*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/8 - (7*th)/200 + 509/800))/196 + (25*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^2)/784 + (625*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 501/200)^3)/2352 - (625*(((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/2 - (7*th)/50 + 509/200)^3)/2352 - (625*((7*th)/100 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/4 - 509/400)^3)/294 + ((3563*th)/1250 - (49*th^2)/625 - 51761/2000)^(1/2)/56 + 501/5600
fplot(profile4_2,[-30 50],'b')
grid on
hold on
see picture-->
And what are these Pointed Lines ? Asymptotes ? isn*t that also a value ?

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回答（1 个）

Star Strider
Star Strider 2018-7-5
One option is to use solve first, then vpa on each solution:
Ss = solve(poly);
Ss1 = vpa(Ss(1))
Ss2 = vpa(Ss(2))
Ss1 =
17.596831054855911338197657259377
Ss2 =
18.059378423543239434615372667097

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