How do you graph a function that refers to the function in its value?

How do you graph a function that refers to the function in its value?

For example,

Function:

y(p)=[y(p-2)+y(p-1)]/2

y(1)=0

y(2)=[y(0)+y(1)]/2

How would you graph this, when p is equal to 1-20?

Answer 1

[galaxy]

what is y(0)?

please refer following example.

y(1) = 0;
y(2) = 1;
for i = 3:20
   y(i) = (y(i-1)+y(i-2))/2;
end
plot(y)

Answer 2

[Shubham Gupta]

MATLAB doesn't allow 0 as an index. Infact, index must be a natural number.

y(0) % is an invalid index because 0
y(0.5) % is an invalid index because fraction
y(-1) % is an invalid index because negative

Now, to solve the problem for indexing that starts with 0, you can shift indeces by 1 unit forward. So, now your code will become.

y(0+1) = 0; % equivalent to y0
y(1+1) = 1; % equivalent to y1
for i = 2:20
    y(p+1) = (y(p-2+1) + y(p-1+1))/2;  % will calculate y(3), y(4),......, y(21) equivalent to y2, y3,....., y20 
end

Now, once you have stored the data in y variable, you can plot it using the 'plot' function

plot(y)

Let me know if you have any doubts