plotting a polynomial function

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

Answer 1

[mohammad]

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))

[Morne' Breitenbach]

What is ment by x_1 = 0:0.1:33.5;

[madhan ravi]

Guck mal hier Breitenbach:

doc colon

[Morne' Breitenbach]

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?

Answer 2

[Rubén Lumbiarres]

x=-5:.1:5;

p=[1 -1 -11 9 18] % polynomial function

plot(x,polyval(p,x))

grid on

[Brian Trease]

Thanks!

I made it one step easier, with no need to specify spacing...

fplot(@(x) polyval(p,x), [-5 5])
grid on

Answer 3

[Fangjun Jiang]

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')

[mohammad]

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.

Answer 4

[Walter Roberson]

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)

[mohammad]

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]

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().

Answer 5

[Ch]

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

Answer 6

[Pink_panther]

%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)