Difference between using "vpasolve" in these 2 codes?
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Eman S
am 7 Mai 2018
Bearbeitet: Eman S
am 2 Feb. 2020
In the following code, I had defined f(x) using syms and to solve this equation, I used vpasolve(f).
syms f(x)
alpha=5;
mio=0.6;
B=2;
if alpha==5
if mio==0.6
if B==2
bast=(x/0.5).^(alpha*(mio-1));
mqam_part1=3*B*((sqrt(3)/2).^(alpha*mio));
mqam_part2=((0.5*sqrt(3)).^(-alpha))+((1.5*sqrt(3)).^(-alpha));
mqam_part3=3*(((x/0.5)).^(alpha*mio));
mqam_part4=((sqrt(3)-(x/0.5)).^-alpha);
mqam_part5=((2*sqrt(3))-(x/0.5)).^-alpha;
mqam_part6=mqam_part4+mqam_part5;
mqam_part7=2*((3-(x/0.5)).^-alpha);
mqam_part8=6*(((x/0.5)).^(alpha*mio));
mqam_part9=6*B*(2.^-alpha);
eqn_LHS=bast/(mqam_part1+mqam_part2)+(mqam_part3*(mqam_part6+mqam_part7));
eqn_RHS=B/((mqam_part8*mqam_part6)+mqam_part9);
f(x)=eqn_LHS-eqn_RHS;
sol_positive = vpasolve(f);
end
end
end
After running this code, it has the following output:
sol_positive =
-0.088528537330827491688440727135052
0.089168332029743739883884412606126
0.33826394036632543530763273039833
1.1599250419465014133554207319948
1.2989629568831597716493684806851
1.6240554937821142318780347702386
4.1380104774956983606108108853334
0.36340277619978535323175586579368 - 0.17885283113851906156582968732142i
1.2992644818621369190151455557302 - 0.31440379416295109163597261773161i
1.4897230890912773483095146949368 - 1.3150774672581101958523122516833i
1.6282605813254473735848321984622 - 0.083684308295293467728903801421506i
1.6955614120462881985070978123707 - 0.34019756525211237400051800951627i
2.8366220103150973884193959600945 - 2.0075730328576518221908039773448i
0.96894287293815413579933338616546 - 1.0029719645739903595813767103315i
2.8366220103150973884193959600945 + 2.0075730328576518221908039773448i
1.2992644818621369190151455557302 + 0.31440379416295109163597261773161i
1.4897230890912773483095146949368 + 1.3150774672581101958523122516833i
0.36340277619978535323175586579368 + 0.17885283113851906156582968732142i
0.96894287293815413579933338616546 + 1.0029719645739903595813767103315i
1.6282605813254473735848321984622 + 0.083684308295293467728903801421506i
1.1475584718883716605696238712257 + 0.23111120566119037717218445710823i
1.6955614120462881985070978123707 + 0.34019756525211237400051800951627i
0.67755561933436425842885030639685 + 0.89740492763981823171766701235696i
0.35356088917929933509194226805741 + 0.46392937489127504001635787211895i
1.1475584718883716605696238712257 - 0.23111120566119037717218445710823i
0.35356088917929933509194226805741 - 0.46392937489127504001635787211895i
0.67755561933436425842885030639685 - 0.89740492763981823171766701235696i
But, in the following code,I had defined the parameters of the equation *B,x,mio using syms and to solve this equation, I used vpasolve(eqn1,x,[0 Inf]).
syms alpha mio B x
alpha=5;
mio=0.6;
B=2;
if alpha==5
if mio==0.6
if B==2
bast=(x/0.5).^(alpha*(mio-1));
mqam_part1=3*B*((sqrt(3)/2).^(alpha*mio));
mqam_part2=((0.5*sqrt(3)).^(-alpha))+((1.5*sqrt(3)).^(-alpha));
mqam_part3=3*(((x/0.5)).^(alpha*mio));
mqam_part4=((sqrt(3)-(x/0.5)).^-alpha);
mqam_part5=((2*sqrt(3))-(x/0.5)).^-alpha;
mqam_part6=mqam_part4+mqam_part5;
mqam_part7=2*((3-(x/0.5)).^-alpha);
mqam_part8=6*(((x/0.5)).^(alpha*mio));
mqam_part9=6*B*(2.^-alpha);
eqn_LHS=bast/(mqam_part1+mqam_part2)+(mqam_part3*(mqam_part6+mqam_part7));
eqn_RHS=B/((mqam_part8*mqam_part6)+mqam_part9);
eqn1=eqn_LHS==eqn_RHS;
sol_positive = vpasolve(eqn1,x,[0 Inf]);
end
end
end
After running this code, it has the following output:
sol_positive =
0.089168332029743739883884412606126
0.33826394036632543530763273039833
1.1599250419465014133554207319948
1.2989629568831597716493684806851
1.6240554937821142318780347702386
4.1380104774956983606108108853334
So, my question is: what is the difference between using vpasolve in the 2 codes and how does it work to give these outputs??
2 Kommentare
Image Analyst
am 1 Feb. 2020
Original question
What is the difference between using "vpasolve" in the following 2 codes?
In the following code, I had defined f(x) using syms and to solve this equation, I used vpasolve(f).
syms f(x)
alpha=5;
mio=0.6;
B=2;
if alpha==5
if mio==0.6
if B==2
bast=(x/0.5).^(alpha*(mio-1));
mqam_part1=3*B*((sqrt(3)/2).^(alpha*mio));
mqam_part2=((0.5*sqrt(3)).^(-alpha))+((1.5*sqrt(3)).^(-alpha));
mqam_part3=3*(((x/0.5)).^(alpha*mio));
mqam_part4=((sqrt(3)-(x/0.5)).^-alpha);
mqam_part5=((2*sqrt(3))-(x/0.5)).^-alpha;
mqam_part6=mqam_part4+mqam_part5;
mqam_part7=2*((3-(x/0.5)).^-alpha);
mqam_part8=6*(((x/0.5)).^(alpha*mio));
mqam_part9=6*B*(2.^-alpha);
eqn_LHS=bast/(mqam_part1+mqam_part2)+(mqam_part3*(mqam_part6+mqam_part7));
eqn_RHS=B/((mqam_part8*mqam_part6)+mqam_part9);
f(x)=eqn_LHS-eqn_RHS;
sol_positive = vpasolve(f);
end
end
end
After running this code, it has the following output:
sol_positive =
-0.088528537330827491688440727135052
0.089168332029743739883884412606126
0.33826394036632543530763273039833
1.1599250419465014133554207319948
1.2989629568831597716493684806851
1.6240554937821142318780347702386
4.1380104774956983606108108853334
0.36340277619978535323175586579368 - 0.17885283113851906156582968732142i
1.2992644818621369190151455557302 - 0.31440379416295109163597261773161i
1.4897230890912773483095146949368 - 1.3150774672581101958523122516833i
1.6282605813254473735848321984622 - 0.083684308295293467728903801421506i
1.6955614120462881985070978123707 - 0.34019756525211237400051800951627i
2.8366220103150973884193959600945 - 2.0075730328576518221908039773448i
0.96894287293815413579933338616546 - 1.0029719645739903595813767103315i
2.8366220103150973884193959600945 + 2.0075730328576518221908039773448i
1.2992644818621369190151455557302 + 0.31440379416295109163597261773161i
1.4897230890912773483095146949368 + 1.3150774672581101958523122516833i
0.36340277619978535323175586579368 + 0.17885283113851906156582968732142i
0.96894287293815413579933338616546 + 1.0029719645739903595813767103315i
1.6282605813254473735848321984622 + 0.083684308295293467728903801421506i
1.1475584718883716605696238712257 + 0.23111120566119037717218445710823i
1.6955614120462881985070978123707 + 0.34019756525211237400051800951627i
0.67755561933436425842885030639685 + 0.89740492763981823171766701235696i
0.35356088917929933509194226805741 + 0.46392937489127504001635787211895i
1.1475584718883716605696238712257 - 0.23111120566119037717218445710823i
0.35356088917929933509194226805741 - 0.46392937489127504001635787211895i
0.67755561933436425842885030639685 - 0.89740492763981823171766701235696i
But, in the following code,I had defined the parameters of the equation *B,x,mio using syms and to solve this equation, I used vpasolve(eqn1,x,[0 Inf]).
syms alpha mio B x
alpha=5;
mio=0.6;
B=2;
if alpha==5
if mio==0.6
if B==2
bast=(x/0.5).^(alpha*(mio-1));
mqam_part1=3*B*((sqrt(3)/2).^(alpha*mio));
mqam_part2=((0.5*sqrt(3)).^(-alpha))+((1.5*sqrt(3)).^(-alpha));
mqam_part3=3*(((x/0.5)).^(alpha*mio));
mqam_part4=((sqrt(3)-(x/0.5)).^-alpha);
mqam_part5=((2*sqrt(3))-(x/0.5)).^-alpha;
mqam_part6=mqam_part4+mqam_part5;
mqam_part7=2*((3-(x/0.5)).^-alpha);
mqam_part8=6*(((x/0.5)).^(alpha*mio));
mqam_part9=6*B*(2.^-alpha);
eqn_LHS=bast/(mqam_part1+mqam_part2)+(mqam_part3*(mqam_part6+mqam_part7));
eqn_RHS=B/((mqam_part8*mqam_part6)+mqam_part9);
eqn1=eqn_LHS==eqn_RHS;
sol_positive = vpasolve(eqn1,x,[0 Inf]);
end
end
end
After running this code, it has the following output:
sol_positive =
0.089168332029743739883884412606126
0.33826394036632543530763273039833
1.1599250419465014133554207319948
1.2989629568831597716493684806851
1.6240554937821142318780347702386
4.1380104774956983606108108853334
So, my question is: what is the difference between using vpasolve in the 2 codes and how does it work to give these outputs??
Akzeptierte Antwort
Walter Roberson
am 7 Mai 2018
The fact that you got multiple outputs tells us that the equations define a polynomial. In the case of a polynomial, vpasolve returns all of solutions that meet the defined constraints. In the first case there are no constraints so it returns all of solutions whether real or complex valued. In the second case you included a range, which is equivalent to having added in(x, 0, inf), or (x >= 0 & x <= inf), which acts to eliminate the negative and complex valued solutions.
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