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plotting a polynomial function

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mohammad
mohammad el 14 de Dic. de 2011
Editada: Walter Roberson el 23 de Oct. de 2023
How can I plot a polynomial function in MATLAB? for example:
89.9659+0.1110371T-0.001472155T^2+ 1.1E-5T^3-4.381E-8T^4+1E-10T^5

Respuesta aceptada

mohammad
mohammad el 18 de Jun. de 2012
Editada: Walter Roberson el 23 de Oct. de 2023
y_1 = @(x) -0.6729+4.8266*x-0.4855*x.^2+0.0312*x.^3
y_1 = function_handle with value:
@(x)-0.6729+4.8266*x-0.4855*x.^2+0.0312*x.^3
x_1 = 0:0.1:33.5;
plot(x_1,y_1(x_1))
  3 comentarios
madhan ravi
madhan ravi el 4 de Jun. de 2020
Guck mal hier Breitenbach:
doc colon
Morne' Breitenbach
Morne' Breitenbach el 5 de Jun. de 2020
Sorry not German or Dutch, my surname is Afrikaanse. so I presume you ment "look here", we write it as "Kyk heir"(said Cake Hirr(like the i in his with a pronounced roll of the r). So the zero means that our number set begins at zero and ends at 33.5, and we get from zero to 33.5 by adding incraments of 0.1? Is this correct?

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Más respuestas (5)

Rubén Lumbiarres
Rubén Lumbiarres el 13 de Sept. de 2018
Editada: Walter Roberson el 15 de Sept. de 2018
x=-5:.1:5;
p=[1 -1 -11 9 18] % polynomial function
plot(x,polyval(p,x))
grid on
  1 comentario
Brian Trease
Brian Trease el 24 de Nov. de 2020
Thanks!
I made it one step easier, with no need to specify spacing...
fplot(@(x) polyval(p,x), [-5 5])
grid on

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Fangjun Jiang
Fangjun Jiang el 14 de Dic. de 2011
Of course ezplot(), but you need to fix your formula.
ezplot('89.9659+0.1110371*T-0.001472155*T^2+ 1.1E-5*T^3-4.381E-8*T^4+1E-10*T^5')
  1 comentario
mohammad
mohammad el 14 de Dic. de 2011
Thanks Fangjun, how can I plot from T=100 to T=1000?
When I use xlim([100 1000]), It doesn't plot in this interval.

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Walter Roberson
Walter Roberson el 14 de Dic. de 2011
Editada: Walter Roberson el 23 de Oct. de 2023
You are asking to plot data that has a range of about 10^10 at one end, and about 10^20 at the other end. What are you expecting to see of interest?
T=linspace(100,1000,100);
p=89.9659+0.1110371*T-0.001472155*T.^2+ 1.1E-5*T.^3-4.381E-8*T.^4+1E-10*T.^5;
plot(T,p)
  2 comentarios
mohammad
mohammad el 14 de Dic. de 2011
Walter, do you mean Because of being so great number (10^2 to 10^20 )it's impossible to see in range of 100 to 1000?
in this interval, value of function is between 0.95 to 0.98 .
Fangjun Jiang
Fangjun Jiang el 14 de Dic. de 2011
No. Because you have small coefficients, the range of p is not from 10^2 to 10^20. The maximum value of p is around 7e4.
The point is, you can specify any range of T as you want, use linspace() or 100:100:1000, then use array power ".^" not the matrix power "^" to evaluate p, and then you can use plot().

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Ch
Ch el 4 de Sept. de 2022
x=-5:.1:5;
p=[1 -1 -11 9 18] % polynomial function
p = 1×5
1 -1 -11 9 18
plot(x,polyval(p,x))
grid on

Pink_panther
Pink_panther el 23 de Oct. de 2023
%solve1
fplot(@(x)89.9659+0.1110371.*x-0.001472155.*x.^2+1.1E-5.*x.^3-4.381E-8.*x.^4+1E-10.*x.^5)

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