How can I derive solution in matrix form?

i want to get solutions with varying x from 0.201 to 0.210

the problem i have is like the below

x=0.201:0.001:0.210;
eqn=x^2*y^4+~~~~~~
and i want to get solutions of y in matrix form
and plot it with x
plot(x,y)

How can i get this solution in matrix form?

Answer 1

[Mischa Kim]

Hello Junsoo, what relevance has eqn in computing y as a function of x?

In general, you need to use the dot notation when e.g. multiplying vectors. Try for example:

 x = 0.201:0.001:0.210;
 y = x.^2.*sqrt(3*x);
 plot(x,y)

[Junsoo Lee]

Well my problem is The eqn is like this x*(y^4+y)=0

[Roger Stafford]

If x*(y^4+y)=0 is your equation, the solutions for y will be totally independent of the values of x, so it makes no sense to plot y against x.

[Junsoo Lee]

Im sorry The eqn is x*(y^4+y)=constant

[Junsoo Lee]

The code is like this

clear; clc;

upsilon=0.9;

h=5; r_1=0.2; T_inf=298; T_sur=308; q_r=136.66; sigma=5.67E-08;

T_s2=eye(1,10);

r_2=0.201:0.001:0.210;

sys=4*pi*(r_2).^2.*(upsilon*sigma*((T_s2).^4-(T_sur)^4)+h*(T_s2-T_inf))-q_r;

i want to solve the eqn for T_s2 and get it in the matrix form but i can't figure out how can i get the solution in matrix form.

Answer 2

[James Tursa]

Use the dot versions of the operators to get element-wise operations. E.g.,

eqn=x.^2.*y.^4+~~~~~~  % <-- Note the use of .* and .^ instead of just * and ^

[Junsoo Lee]

Thanks for the answer but my problem is eqn is like this x*y^4+y^2=0

[James Tursa]

So now it sounds like your primary question is one of solving an equation for y in terms of x, and a secondary question is how to plot the solution for a range of x. Is this correct?

So far you have listed two different equations:

x*(y^4+y)=0

and

x*y^4+y^2=0

What is it exactly that you are trying to solve?

[Junsoo Lee]

Im sorry The eqn is x*(y^4+y)=constant

[Junsoo Lee]

The code is like this

clear; clc;

upsilon=0.9;

h=5; r_1=0.2; T_inf=298; T_sur=308; q_r=136.66; sigma=5.67E-08;

T_s2=eye(1,10);

r_2=0.201:0.001:0.210;

sys=4*pi*(r_2).^2.*(upsilon*sigma*((T_s2).^4-(T_sur)^4)+h*(T_s2-T_inf))-q_r;

i want to solve the eqn for T_s2 and get it in the matrix form but i can't figure out how can i get the solution in matrix form.