plotting a polynomial function
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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
采纳的回答
y_1 = @(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 个评论
Morne' Breitenbach
2020-6-4
What is ment by x_1 = 0:0.1:33.5;
madhan ravi
2020-6-4
Guck mal hier Breitenbach:
doc colon
Morne' Breitenbach
2020-6-5
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?
更多回答（5 个）
Rubén Lumbiarres
2018-9-13
编辑：Walter Roberson
2018-9-15
x=-5:.1:5;
p=[1 -1 -11 9 18] % polynomial function
plot(x,polyval(p,x))
grid on
1 个评论
Brian Trease
2020-11-24
Thanks!
I made it one step easier, with no need to specify spacing...
fplot(@(x) polyval(p,x), [-5 5])
grid on
Fangjun Jiang
2011-12-14
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')
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 个评论
mohammad
2011-12-14
Fangjun Jiang
2011-12-14
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().
x=-5:.1:5;
p=[1 -1 -11 9 18] % polynomial function
plot(x,polyval(p,x))
grid on
%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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