How to plot x(n) for many values of n?

How to plot 𝑥(𝑛) = 𝛼𝑛 𝑥(0) for n=1-30 and x(0)=100?? I have tried this code, but it is repeating it's value again and again... What I am missing?

alpha = 2
x0 = 100; % Initial conditions  
for n = 1:30
    x(n) = (alpha^n)*(x0)
end
disp(x(n))

Answer 1

[madhan ravi]

Shorter code eliminating loop:

Alpha = 2
x0 = 100; % Initial conditions  
n = 1:30;
x = Alpha.^n*x0;
plot(n,x)

Note: You were doing it correctly all you had to use was disp(x)

[SAS]

I had tried to convert it in matrix as well. But i am facing this error message.

Incorrect dimensions for raising a matrix to a power. Check that the matrix is square and the power is a scalar. To perform elementwise matrix powers, use '.^'.

[madhan ravi]

So use .^ ;)

[SAS]

Great man... I got my results..

And if we have multiple values of alpha? and we have to draw x(n)? What should we do? Should we use a loop or should we write separate values for alpha again and again? And for 5 values of alpha, we will get 5 curves?

I was trying to this code, but results are not as per my requirements

Alpha = [1.05; 1.1; 1.2; 1.4]

x0 = 100; % Initial conditions

n = 1:30;

x = Alpha.^n*x0

plot(n,x)

[madhan ravi]

Alpha = [1.05; 1.1; 1.2; 1.4] 
x0 = 100; % Initial conditions 
for Alpha = Alpha 
    figure 
    n = 1:30; 
    x = Alpha.^n*x0; 
    plot(n,x) 
end

[SAS]

I am asking again and again, but as I am new to Matlab, how to divide the plot in sub-plots? I have used this code but it is a bit awkward. Any other proper way?

Alpha = [1.05; 1.1; 1.2; 1.4]

x0 = 100; % Initial conditions

n = 1:30;

x = Alpha.^n*x0

x1=x(1,:)

x2=x(2,:)

x3=x(3,:)

x4=x(4,:)

subplot(2,2,1)

plot(n,x1)

subplot(2,2,2)

plot(n,x2)

subplot(2,2,3)

plot(n,x3)

subplot(2,2,4)

plot(n,x4)

[madhan ravi]

plot(n,x.')

Note: Since the scales are different , using subplots is the way to go.

[SAS]

Still the same answers, Showing all graphs in one plot...

[madhan ravi]

Man... what do you want to do? Did you read https://www.mathworks.com/matlabcentral/answers/543416-how-to-plot-x-n-for-many-values-of-n#comment_886145 ?

[SAS]

Issues resolved.

Answer 2

[David Hill]

alpha = 2
x0 = 100; % Initial conditions  
for n = 1:30
    x(n) = (alpha^n)*(x0)
end
disp(x);
plot(1:30,x);

[SAS]

x(n) is returning too many values. Shouldn't it give x(1) to x(30)? only 30 values?

[David Hill]

x has only 30 values...use ; to suppress

alpha = 2;
x0 = 100; % Initial conditions  
for n = 1:30
    x(n) = (alpha^n)*(x0);
end
disp(x);
plot(1:30,x);

[SAS]

Thanks dear...